DB Olympics

Queries · q023 · Chief Financial Officer · week 1, night 4

Merchant-Level Quarterly Refund Rate, 2025 (excluding Apparel & Footwear)

“Which specific non-Apparel merchant(s) caused the refund-rate spike in 2025-Q2/Q3?”

Manager · asked the questionTobias LindqvistChief Financial Officer. New this month, previously finance director at a retailer. Preparing the 2025 annual accounts and the 2026 budget.
Analyst · planned the reportKofi MensahHypothesis-driven: states what he expects and designs reports that would prove him wrong.
Engineer · wrote the SQLInesThinks in window functions: ranks, running totals, LAG/LEAD for comparisons, percent-of-total.

Fictional people at a fictional company, each played by a language-model agent. Who they are and what they are told

  1. Tobias Lindqvist writes to Kofi Mensah

    The manager, at the start of week 1

    Subject: Finding my bearings – first set of questions for the week

    Hi Kofi,

    Good to be working with you. I'm still building my mental map of the business, so I'd rather ask a few broad questions well than a lot of narrow ones badly. Given the slot budget, here's what I'd prioritize this week, roughly in order:

    1. How did we actually do in 2025, and where is the money coming from? I want to see our own revenue split between the subscription/plan fees and the payment-processing fees, over the year, and ideally how that's trending month to month. This is the backbone of the annual accounts narrative and will shape how I talk about 2025 to the board.
    2. How concentrated is our business in a few large merchants, and how healthy are they? I keep hearing "a handful of large merchants drive most of the volume" — I'd like to understand who they are, how much of our gross volume and revenue they represent, and whether that concentration is growing or shrinking. This matters for risk assessment going into the budget.
    3. What do refunds and returns look like across the merchant base? I want a sense of refund rates — overall and whether certain verticals or merchants are outliers — since this affects both our net revenue and how much cash we actually end up paying out.
    4. How exposed are we to currency movements? Merchants bill in their own currencies, and shoppers come from ~40 countries. I'd like a picture of how our volume and revenue break down by currency, so I can gauge our FX exposure for the 2026 budget and think about whether we need any hedging conversation.
    5. Are our B2B merchants paying us and their own customers on time? I know a few of our merchants are wholesalers running on B2B terms. I'd like to understand how their receivables look — how much is outstanding and how overdue it tends to get — since this could be a real cash-flow risk if it's worse than I'd expect.

    For this week, let's focus on #1 and #2 — those are the two I most need before I can speak credibly about 2025 and the 2026 budget. If there's room, #3 would be next; #4 and #5 can wait for a follow-up week if slots are tight.

    Let me know if any of these need me to narrow scope further before you brief the data engineers.

    Thanks, Tobias

  2. Kofi Mensah plans the night

    The analyst · week 1, night 4, request 2 of 3

    Report 1 confirms the fix: the corrected monthly series now ties exactly to the independently-verified 2025 annual totals (€3,972,987.99 gross / €93,583.20 fee / 2.4% blended fee rate), and payout counts roughly doubled vs. the original buggy report — consistent with it having silently dropped close to half of all payouts for a reason we never fully root-caused, but which is now moot since the corrected figures cross-foot cleanly. #1 is now safe to put in front of Tobias, with the one caveat I'll carry into the memo: nothing in this warehouse captures Tidewick's own platform-plan billing of merchants (the plans/subscriptions/invoices tables here model each merchant's billing of their customers, not Tidewick's billing of the merchant) — so I can only report the processing-fee half of the revenue split, not the plan-fee half.

    On refunds, I did the arithmetic behind Report 2 and 3 by hand: subtracting Apparel's numbers from the company totals shows the non-Apparel refund rate was stable at ~2-3% through 2024, but spiked to 4.9% in 2025-Q2 and 9.1% in 2025-Q3 before dropping back to 4.2% in Q4 — a 3-4x jump that Apparel's own flat/improving trend doesn't explain. Apparel itself looks structural (19-26% every quarter, actually lowest in the latest quarter), so that part of #3 is answered and not worsening. But this non-Apparel spike is new information worth chasing on this last night before the memo, since it could be a specific merchant issue (e.g. a product recall or quality problem) rather than normal seasonal variation. I'm spending two slots to localize it (by vertical, then by merchant) and a third to cross-check the payments-based refund figures against the independent order_returns table, given how costly the earlier monthly-revenue bug was — I don't want to hand Tobias a refund narrative built on a single, unverified source.

    Merchant-Level Quarterly Refund Rate, 2025 (excluding Apparel & Footwear)
    Question
    Which specific non-Apparel merchant(s) caused the refund-rate spike in 2025-Q2/Q3?
    One row per
    one tenant (merchant), for 2025, with quarterly refund rates as columns
    Columns
    • merchant_name
    • vertical
    • gross_captured_eur_fy2025
    • refund_rate_q1_pct
    • refund_rate_q2_pct
    • refund_rate_q3_pct
    • refund_rate_q4_pct
    • refund_rate_fy2025_pct
  3. Ines writes the SQL

    The engineer · 2 dry runs on the empty schema, then the submission

    Dry run 1 · STATUS: REJECTED
    WITH fx AS (
      SELECT quote_code, as_of, rate
      FROM exchange_rates
      WHERE base_code = 'EUR'
    ),
    base AS (
      SELECT
        p.tenant_id,
        p.currency_code,
        p.amount,
        p.amount_refunded,
        CAST(p.captured_at AS date) AS captured_date,
        EXTRACT(QUARTER FROM p.captured_at)::int AS q
      FROM payments p
      JOIN tenants t ON t.id = p.tenant_id
      WHERE (t.industry IS DISTINCT FROM 'Apparel & Footwear')
        AND p.status IN ('captured', 'refunded', 'partially_refunded')
        AND p.captured_at >= TIMESTAMP '2025-01-01'
        AND p.captured_at < TIMESTAMP '2026-01-01'
    ),
    converted AS (
      SELECT
        b.tenant_id,
        b.q,
        CASE WHEN b.currency_code = 'EUR' THEN b.amount ELSE b.amount / fx.rate END AS amount_eur,
        CASE WHEN b.currency_code = 'EUR' THEN b.amount_refunded ELSE b.amount_refunded / fx.rate END AS refunded_eur
      FROM base b
      LEFT JOIN fx ON fx.quote_code = b.currency_code AND fx.as_of = b.captured_date
    ),
    tenant_quarter AS (
      SELECT tenant_id, q,
             SUM(amount_eur) AS gross_eur,
             SUM(refunded_eur) AS refunded_eur,
             COUNT(*) AS cnt
      FROM converted
      GROUP BY tenant_id, q
    ),
    tenant_total AS (
      SELECT tenant_id,
             SUM(gross_eur) AS gross_eur_fy,
             SUM(refunded_eur) AS refunded_eur_fy,
             SUM(cnt) AS cnt_fy
      FROM tenant_quarter
      GROUP BY tenant_id
    ),
    qualified AS (
      SELECT tenant_id FROM tenant_total WHERE cnt_fy >= 20
    ),
    pivot AS (
      SELECT
        tt.tenant_id,
        tt.gross_eur_fy,
        tt.refunded_eur_fy,
        MAX(CASE WHEN tq.q = 1 THEN tq.gross_eur END) AS q1_gross,
        MAX(CASE WHEN tq.q = 1 THEN tq.refunded_eur END) AS q1_ref,
        MAX(CASE WHEN tq.q = 2 THEN tq.gross_eur END) AS q2_gross,
        MAX(CASE WHEN tq.q = 2 THEN tq.refunded_eur END) AS q2_ref,
        MAX(CASE WHEN tq.q = 3 THEN tq.gross_eur END) AS q3_gross,
        MAX(CASE WHEN tq.q = 3 THEN tq.refunded_eur END) AS q3_ref,
        MAX(CASE WHEN tq.q = 4 THEN tq.gross_eur END) AS q4_gross,
        MAX(CASE WHEN tq.q = 4 THEN tq.refunded_eur END) AS q4_ref
      FROM tenant_total tt
      JOIN tenant_quarter tq ON tq.tenant_id = tt.tenant_id
      WHERE tt.tenant_id IN (SELECT tenant_id FROM qualified)
      GROUP BY tt.tenant_id, tt.gross_eur_fy, tt.refunded_eur_fy
    )
    SELECT
      t.name AS merchant_name,
      t.industry AS vertical,
      ROUND(p.gross_eur_fy, 2) AS gross_captured_eur_fy2025,
      ROUND(100.0 * p.q1_ref / NULLIF(p.q1_gross, 0), 2) AS refund_rate_q1_pct,
      ROUND(100.0 * p.q2_ref / NULLIF(p.q2_gross, 0), 2) AS refund_rate_q2_pct,
      ROUND(100.0 * p.q3_ref / NULLIF(p.q3_gross, 0), 2) AS refund_rate_q3_pct,
      ROUND(100.0 * p.q4_ref / NULLIF(p.q4_gross, 0), 2) AS refund_rate_q4_pct,
      ROUND(100.0 * p.refunded_eur_fy / NULLIF(p.gross_eur_fy, 0), 2) AS refund_rate_fy2025_pct
    FROM pivot p
    JOIN tenants t ON t.id = p.tenant_id
    ORDER BY refund_rate_q3_pct DESC NULLS LAST, merchant_name ASC
    LIMIT 30
    Dry run 2 · 2 changes from the dry run before · STATUS: COMPILES (dry run on the empty schema, no data read)
    WITH fx AS (  SELECT quote_code, as_of, rate  FROM exchange_rates  WHERE base_code = 'EUR'),base AS (  SELECT    p.tenant_id,    p.currency_code,    p.amount,    p.amount_refunded,    CAST(p.captured_at AS date) AS captured_date,    EXTRACT(QUARTER FROM p.captured_at)::int AS q  FROM payments p  JOIN tenants t ON t.id = p.tenant_id  WHERE (t.industry IS DISTINCT FROM 'Apparel & Footwear')    AND p.status IN ('captured', 'refunded', 'partially_refunded')    AND p.captured_at >= TIMESTAMP '2025-01-01'    AND p.captured_at < TIMESTAMP '2026-01-01'),converted AS (  SELECT    b.tenant_id,    b.q,    CASE WHEN b.currency_code = 'EUR' THEN b.amount ELSE b.amount / fx.rate END AS amount_eur,    CASE WHEN b.currency_code = 'EUR' THEN b.amount_refunded ELSE b.amount_refunded / fx.rate END AS refunded_eur  FROM base b  LEFT JOIN fx ON fx.quote_code = b.currency_code AND fx.as_of = b.captured_date),tenant_quarter AS (  SELECT tenant_id, q,         SUM(amount_eur) AS gross_eur,         SUM(refunded_eur) AS refunded_eur,         COUNT(*) AS cnt  FROM converted  GROUP BY tenant_id, q),tenant_total AS (  SELECT tenant_id,         SUM(gross_eur) AS gross_eur_fy,         SUM(refunded_eur) AS refunded_eur_fy,         SUM(cnt) AS cnt_fy  FROM tenant_quarter  GROUP BY tenant_id),qualified AS (  SELECT tenant_id FROM tenant_total WHERE cnt_fy >= 20),pivot AS (pivoted AS (  SELECT    tt.tenant_id,    tt.gross_eur_fy,    tt.refunded_eur_fy,    MAX(CASE WHEN tq.q = 1 THEN tq.gross_eur END) AS q1_gross,    MAX(CASE WHEN tq.q = 1 THEN tq.refunded_eur END) AS q1_ref,    MAX(CASE WHEN tq.q = 2 THEN tq.gross_eur END) AS q2_gross,    MAX(CASE WHEN tq.q = 2 THEN tq.refunded_eur END) AS q2_ref,    MAX(CASE WHEN tq.q = 3 THEN tq.gross_eur END) AS q3_gross,    MAX(CASE WHEN tq.q = 3 THEN tq.refunded_eur END) AS q3_ref,    MAX(CASE WHEN tq.q = 4 THEN tq.gross_eur END) AS q4_gross,    MAX(CASE WHEN tq.q = 4 THEN tq.refunded_eur END) AS q4_ref  FROM tenant_total tt  JOIN tenant_quarter tq ON tq.tenant_id = tt.tenant_id  WHERE tt.tenant_id IN (SELECT tenant_id FROM qualified)  GROUP BY tt.tenant_id, tt.gross_eur_fy, tt.refunded_eur_fy)SELECT  t.name AS merchant_name,  t.industry AS vertical,  ROUND(p.gross_eur_fy, 2) AS gross_captured_eur_fy2025,  ROUND(100.0 * p.q1_ref / NULLIF(p.q1_gross, 0), 2) AS refund_rate_q1_pct,  ROUND(100.0 * p.q2_ref / NULLIF(p.q2_gross, 0), 2) AS refund_rate_q2_pct,  ROUND(100.0 * p.q3_ref / NULLIF(p.q3_gross, 0), 2) AS refund_rate_q3_pct,  ROUND(100.0 * p.q4_ref / NULLIF(p.q4_gross, 0), 2) AS refund_rate_q4_pct,  ROUND(100.0 * p.refunded_eur_fy / NULLIF(p.gross_eur_fy, 0), 2) AS refund_rate_fy2025_pctFROM pivot pFROM pivoted pJOIN tenants t ON t.id = p.tenant_idORDER BY refund_rate_q3_pct DESC NULLS LAST, merchant_name ASCLIMIT 30

    “Query compiles correctly with the expected 8 columns. Submitting now.”

    Submitted · the SQL of the last dry run, unchanged · Submitted to tonight's batch. Your work on this request is done.

    “Submitted. Summary of what the query does: - Filters payments to 2025 captures with status in (captured, refunded, partially_refunded), joined to tenants, excluding industry = 'Apparel & Footwear'. - Converts amount and amount_refunded to EUR per row using the day's exchange_rates (base EUR), matching on captured_at's date. - Aggregates gross and refunded EUR per tenant per quarter, then totals for the year. - Keeps only tenants with ≥20 qualifying payments in 2025. - Pivots quarters into columns and computes refund-rate % (refunded/gross) for Q1–Q4 and FY2025. - Orders by Q3 refund rate descending (tie-break by merchant name), returns top 30 rows, one row per merchant. Note sent to the analyst: the excluded-tenant count from the ≥20-payment threshold isn't representable at this per-tenant grain (would need a separate single-row report), and quarters with zero gross for a tenant show a null rate rather than a divide-by-zero error.”

  4. The report comes back overnight

    As Kofi Mensah saw it, from the small dataset the agents worked on

    merchant_name          | vertical                  | gross_captured_eur_fy2025 | refund_rate_q1_pct | refund_rate_q2_pct | refund_rate_q3_pct | refund_rate_q4_pct | refund_rate_fy2025_pct
    -----------------------+---------------------------+---------------------------+--------------------+--------------------+--------------------+--------------------+-----------------------
    Fell & Fjell           | Sports & Outdoor          |                  36116.68 |                2.4 |               7.97 |              34.28 |               4.36 |                   16.2
    Trailmark              | Sports & Outdoor          |                   7428.21 |               NULL |               2.28 |              24.84 |              39.42 |                  31.37
    OfficeHub Nordic       | Office Supplies (B2B)     |                 426010.27 |                0.0 |               6.59 |              20.98 |                0.0 |                   6.96
    Linden & Loom          | Home & Living             |                  37516.18 |               5.88 |              14.69 |               16.4 |               6.84 |                   9.44
    Gratlinie Outdoor      | Sports & Outdoor          |                  94789.94 |              11.77 |               6.02 |              14.48 |              17.01 |                  12.51
    Petalcourt Beauty      | Beauty                    |                  61911.92 |               2.53 |               2.34 |              12.83 |                7.0 |                   6.52
    Ampere & Co.           | Consumer Electronics      |                  28882.99 |               2.06 |               0.85 |              12.42 |               1.33 |                   2.65
    Nordic Bloom Cosmetics | Beauty                    |                  17564.54 |              11.96 |                0.0 |              12.19 |               8.67 |                   7.94
    Willow & Wren          | Home & Living             |                  18796.06 |              18.55 |                2.7 |               11.2 |              12.23 |                  12.78
    Ridgeback Gear         | Sports & Outdoor          |                  27032.69 |              13.81 |               4.64 |              10.42 |              23.61 |                  13.41
    Wiesgrund Wohnen       | Home & Living             |                  37511.41 |               8.82 |               3.22 |               9.85 |               8.08 |                   7.58
    Saffron & Sage         | Beauty                    |                   9866.32 |                0.0 |                0.0 |               9.62 |              11.76 |                   7.48
    Polder Packaging       | Industrial Supplies (B2B) |                  90872.65 |                0.0 |                0.0 |               9.08 |                0.0 |                   2.79
    Juniper Apothecary     | Beauty                    |                  17551.04 |               4.71 |               5.69 |               8.85 |               1.82 |                   4.75
    Fern & Fable           | Home & Living             |                   5535.53 |                0.0 |                0.0 |               8.59 |               7.32 |                    5.6
    Cinder Peak Sports Co. | Sports & Outdoor          |                 123713.44 |              13.07 |              16.06 |               7.57 |              16.02 |                  13.51
    Midland Safety Wear    | Industrial Supplies (B2B) |                 297398.75 |                0.0 |               0.02 |                7.3 |               4.14 |                   3.78
    Chocolaterie Mireille  | Food & Coffee             |                   5122.68 |                0.0 |                0.0 |                6.5 |               0.65 |                   2.16
    Mirelle                | Beauty                    |                   4582.59 |                0.0 |                0.0 |               5.99 |               1.23 |                   1.92
    Spice Route Box        | Food & Coffee             |                  26524.61 |               0.18 |               0.49 |               5.66 |               0.21 |                    1.4
    Ondine Botanicals      | Beauty                    |                   2193.24 |                0.0 |                0.0 |               5.41 |              30.38 |                   8.94
    Basecamp Nord          | Sports & Outdoor          |                   9869.46 |                0.0 |                7.5 |                5.3 |               8.16 |                   5.59
    Velo Noord             | Sports & Outdoor          |                   9780.02 |              14.31 |              31.83 |               5.16 |               8.48 |                  11.39
    The Balm Room          | Beauty                    |                  13879.18 |               6.22 |               2.06 |               4.55 |               6.44 |                   5.28
    Wohnglück              | Home & Living             |                  21016.27 |               5.16 |              11.82 |               4.45 |                7.0 |                   6.79
    Kayak Corner           | Sports & Outdoor          |                  39742.21 |              12.31 |               9.65 |               4.32 |               3.38 |                   8.51
    Fennel & Flint         | Home & Living             |                  64363.83 |               7.67 |              10.76 |               4.29 |               3.96 |                   5.84
    Feather & Fin          | Pet Supplies              |                  10162.91 |                1.1 |                0.0 |                3.9 |                8.7 |                   4.09
    Coastline Interiors    | Home & Living             |                   20804.3 |               2.76 |              15.09 |               3.24 |               6.03 |                   6.39
    Honeycomb Larder       | Food & Coffee             |                  31948.08 |                0.0 |                1.6 |               3.18 |               0.06 |                   0.99
    (30 rows)
  5. What came of it

    The memo and the queries that followed; links found by title, so inferred

    It builds on:

  6. It becomes benchmark query q023

    Changed only where the benchmark needs the same result on every system

    • spellingcast
    • spellingfetch first
    • determinismtie-breaker: tenant names are not unique
    • numericsdocs/NUMERICS.md: rounding removed; results keep full precision
    • numericsdocs/NUMERICS.md: x / exchange rate cast to NUMERIC(18,6) (2×)
    • made explicita selected t.col gets AS col, its standard name made explicit (9×)
    • determinismthe standard leaves the place of NULLs in a sort to the implementation: NULLS LAST ascending, NULLS FIRST descending, as in the reference results (2×)
    • placeholderfetch first
    The benchmark text, against the submitted SQL
    WITH fx AS (  SELECT quote_code, as_of, rate  FROM exchange_rates  WHERE base_code = 'EUR'),base AS (  SELECT    p.tenant_id,    p.currency_code,    p.amount,    p.amount_refunded,    p.tenant_id AS tenant_id,    p.currency_code AS currency_code,    p.amount AS amount,    p.amount_refunded AS amount_refunded,    CAST(p.captured_at AS date) AS captured_date,    EXTRACT(QUARTER FROM p.captured_at)::int AS q    CAST(EXTRACT(QUARTER FROM p.captured_at) AS int) AS q  FROM payments p  JOIN tenants t ON t.id = p.tenant_id  WHERE (t.industry IS DISTINCT FROM 'Apparel & Footwear')    AND p.status IN ('captured', 'refunded', 'partially_refunded')    AND p.captured_at >= TIMESTAMP '2025-01-01'    AND p.captured_at < TIMESTAMP '2026-01-01'),converted AS (  SELECT    b.tenant_id,    b.q,    CASE WHEN b.currency_code = 'EUR' THEN b.amount ELSE b.amount / fx.rate END AS amount_eur,    CASE WHEN b.currency_code = 'EUR' THEN b.amount_refunded ELSE b.amount_refunded / fx.rate END AS refunded_eur    b.tenant_id AS tenant_id,    b.q AS q,    CASE WHEN b.currency_code = 'EUR' THEN b.amount ELSE CAST(b.amount / fx.rate AS NUMERIC(18,6)) END AS amount_eur,    CASE WHEN b.currency_code = 'EUR' THEN b.amount_refunded ELSE CAST(b.amount_refunded / fx.rate AS NUMERIC(18,6)) END AS refunded_eur  FROM base b  LEFT JOIN fx ON fx.quote_code = b.currency_code AND fx.as_of = b.captured_date),tenant_quarter AS (  SELECT tenant_id, q,         SUM(amount_eur) AS gross_eur,         SUM(refunded_eur) AS refunded_eur,         COUNT(*) AS cnt  FROM converted  GROUP BY tenant_id, q),tenant_total AS (  SELECT tenant_id,         SUM(gross_eur) AS gross_eur_fy,         SUM(refunded_eur) AS refunded_eur_fy,         SUM(cnt) AS cnt_fy  FROM tenant_quarter  GROUP BY tenant_id),qualified AS (  SELECT tenant_id FROM tenant_total WHERE cnt_fy >= 20),pivoted AS (  SELECT    tt.tenant_id,    tt.gross_eur_fy,    tt.refunded_eur_fy,    tt.tenant_id AS tenant_id,    tt.gross_eur_fy AS gross_eur_fy,    tt.refunded_eur_fy AS refunded_eur_fy,    MAX(CASE WHEN tq.q = 1 THEN tq.gross_eur END) AS q1_gross,    MAX(CASE WHEN tq.q = 1 THEN tq.refunded_eur END) AS q1_ref,    MAX(CASE WHEN tq.q = 2 THEN tq.gross_eur END) AS q2_gross,    MAX(CASE WHEN tq.q = 2 THEN tq.refunded_eur END) AS q2_ref,    MAX(CASE WHEN tq.q = 3 THEN tq.gross_eur END) AS q3_gross,    MAX(CASE WHEN tq.q = 3 THEN tq.refunded_eur END) AS q3_ref,    MAX(CASE WHEN tq.q = 4 THEN tq.gross_eur END) AS q4_gross,    MAX(CASE WHEN tq.q = 4 THEN tq.refunded_eur END) AS q4_ref  FROM tenant_total tt  JOIN tenant_quarter tq ON tq.tenant_id = tt.tenant_id  WHERE tt.tenant_id IN (SELECT tenant_id FROM qualified)  GROUP BY tt.tenant_id, tt.gross_eur_fy, tt.refunded_eur_fy)SELECT  t.name AS merchant_name,  t.industry AS vertical,  ROUND(p.gross_eur_fy, 2) AS gross_captured_eur_fy2025,  ROUND(100.0 * p.q1_ref / NULLIF(p.q1_gross, 0), 2) AS refund_rate_q1_pct,  ROUND(100.0 * p.q2_ref / NULLIF(p.q2_gross, 0), 2) AS refund_rate_q2_pct,  ROUND(100.0 * p.q3_ref / NULLIF(p.q3_gross, 0), 2) AS refund_rate_q3_pct,  ROUND(100.0 * p.q4_ref / NULLIF(p.q4_gross, 0), 2) AS refund_rate_q4_pct,  ROUND(100.0 * p.refunded_eur_fy / NULLIF(p.gross_eur_fy, 0), 2) AS refund_rate_fy2025_pct  p.gross_eur_fy AS gross_captured_eur_fy2025,  100.0 * p.q1_ref / NULLIF(p.q1_gross, 0) AS refund_rate_q1_pct,  100.0 * p.q2_ref / NULLIF(p.q2_gross, 0) AS refund_rate_q2_pct,  100.0 * p.q3_ref / NULLIF(p.q3_gross, 0) AS refund_rate_q3_pct,  100.0 * p.q4_ref / NULLIF(p.q4_gross, 0) AS refund_rate_q4_pct,  100.0 * p.refunded_eur_fy / NULLIF(p.gross_eur_fy, 0) AS refund_rate_fy2025_pctFROM pivoted pJOIN tenants t ON t.id = p.tenant_idORDER BY refund_rate_q3_pct DESC NULLS LAST, merchant_name ASCLIMIT 30ORDER BY refund_rate_q3_pct DESC NULLS LAST, merchant_name ASC NULLS LAST, t.id NULLS LAST{{fetch_first(30)}}
    WITH fx AS (
      SELECT quote_code, as_of, rate
      FROM exchange_rates
      WHERE base_code = 'EUR'
    ),
    base AS (
      SELECT
        p.tenant_id AS tenant_id,
        p.currency_code AS currency_code,
        p.amount AS amount,
        p.amount_refunded AS amount_refunded,
        CAST(p.captured_at AS date) AS captured_date,
        CAST(EXTRACT(QUARTER FROM p.captured_at) AS int) AS q
      FROM payments p
      JOIN tenants t ON t.id = p.tenant_id
      WHERE (t.industry IS DISTINCT FROM 'Apparel & Footwear')
        AND p.status IN ('captured', 'refunded', 'partially_refunded')
        AND p.captured_at >= TIMESTAMP '2025-01-01'
        AND p.captured_at < TIMESTAMP '2026-01-01'
    ),
    converted AS (
      SELECT
        b.tenant_id AS tenant_id,
        b.q AS q,
        CASE WHEN b.currency_code = 'EUR' THEN b.amount ELSE CAST(b.amount / fx.rate AS NUMERIC(18,6)) END AS amount_eur,
        CASE WHEN b.currency_code = 'EUR' THEN b.amount_refunded ELSE CAST(b.amount_refunded / fx.rate AS NUMERIC(18,6)) END AS refunded_eur
      FROM base b
      LEFT JOIN fx ON fx.quote_code = b.currency_code AND fx.as_of = b.captured_date
    ),
    tenant_quarter AS (
      SELECT tenant_id, q,
             SUM(amount_eur) AS gross_eur,
             SUM(refunded_eur) AS refunded_eur,
             COUNT(*) AS cnt
      FROM converted
      GROUP BY tenant_id, q
    ),
    tenant_total AS (
      SELECT tenant_id,
             SUM(gross_eur) AS gross_eur_fy,
             SUM(refunded_eur) AS refunded_eur_fy,
             SUM(cnt) AS cnt_fy
      FROM tenant_quarter
      GROUP BY tenant_id
    ),
    qualified AS (
      SELECT tenant_id FROM tenant_total WHERE cnt_fy >= 20
    ),
    pivoted AS (
      SELECT
        tt.tenant_id AS tenant_id,
        tt.gross_eur_fy AS gross_eur_fy,
        tt.refunded_eur_fy AS refunded_eur_fy,
        MAX(CASE WHEN tq.q = 1 THEN tq.gross_eur END) AS q1_gross,
        MAX(CASE WHEN tq.q = 1 THEN tq.refunded_eur END) AS q1_ref,
        MAX(CASE WHEN tq.q = 2 THEN tq.gross_eur END) AS q2_gross,
        MAX(CASE WHEN tq.q = 2 THEN tq.refunded_eur END) AS q2_ref,
        MAX(CASE WHEN tq.q = 3 THEN tq.gross_eur END) AS q3_gross,
        MAX(CASE WHEN tq.q = 3 THEN tq.refunded_eur END) AS q3_ref,
        MAX(CASE WHEN tq.q = 4 THEN tq.gross_eur END) AS q4_gross,
        MAX(CASE WHEN tq.q = 4 THEN tq.refunded_eur END) AS q4_ref
      FROM tenant_total tt
      JOIN tenant_quarter tq ON tq.tenant_id = tt.tenant_id
      WHERE tt.tenant_id IN (SELECT tenant_id FROM qualified)
      GROUP BY tt.tenant_id, tt.gross_eur_fy, tt.refunded_eur_fy
    )
    SELECT
      t.name AS merchant_name,
      t.industry AS vertical,
      p.gross_eur_fy AS gross_captured_eur_fy2025,
      100.0 * p.q1_ref / NULLIF(p.q1_gross, 0) AS refund_rate_q1_pct,
      100.0 * p.q2_ref / NULLIF(p.q2_gross, 0) AS refund_rate_q2_pct,
      100.0 * p.q3_ref / NULLIF(p.q3_gross, 0) AS refund_rate_q3_pct,
      100.0 * p.q4_ref / NULLIF(p.q4_gross, 0) AS refund_rate_q4_pct,
      100.0 * p.refunded_eur_fy / NULLIF(p.gross_eur_fy, 0) AS refund_rate_fy2025_pct
    FROM pivoted p
    JOIN tenants t ON t.id = p.tenant_id
    ORDER BY refund_rate_q3_pct DESC NULLS LAST, merchant_name ASC NULLS LAST, t.id NULLS LAST
    FETCH FIRST 30 ROWS ONLY
    10 ms100 ms1 sHyper48.7 msDuckDB38.1 msGizmoSQL47.1 msclickhouse_brew189 msFirebolterrorDataFusion339 msClickHouseerror
    • Firebolt{ "errors": [ { "description": "Line 25, Column 72: Operations between decimals with different precision and scale is not supported at the moment. Explicitly cast one of the decimals to other decimal precision and scale." } ], "query": { "query_id": "1fd33799-9e6a-47d3-96d5-b1a39bbe793b", "query_lab
    • ClickHouseCode: 69. DB::Exception: Decimal result's scale is less than argument's one: while executing function divide on arguments __table5.amount Decimal(14, 4) Decimal64(size = 0), __table8.rate Nullable(Decimal(12, 6)) Nullable(size = 0, Decimal64(size = 0), UInt8(size = 0)). (ARGUMENT_OUT_OF_BOUND)
  7. Everything, as recorded

    The agents' own records, as the role play wrote them; only the personal data of the person who ran it is redacted

    Ines's whole session, 9 turns
    • The request, as Ines received it
      Report request from Kofi Mensah (analyst for the Chief Financial Officer):
      
      Title: Merchant-Level Quarterly Refund Rate, 2025 (excluding Apparel & Footwear)
      Question: Which specific non-Apparel merchant(s) caused the refund-rate spike in 2025-Q2/Q3?
      Grain: one tenant (merchant), for 2025, with quarterly refund rates as columns
      Columns:
      - merchant_name
      - vertical
      - gross_captured_eur_fy2025
      - refund_rate_q1_pct
      - refund_rate_q2_pct
      - refund_rate_q3_pct
      - refund_rate_q4_pct
      - refund_rate_fy2025_pct
      Details: Source: payments joined to tenants, excluding tenants.industry = 'Apparel & Footwear', filtered to status reflecting captured/refunded/partially_refunded with captured_at in calendar year 2025. Convert amount and amount_refunded to EUR via exchange_rates as in the vertical-quarter report. For each tenant, compute refund_rate_pct (amount_refunded_eur / gross_captured_eur * 100) separately for each of Q1-Q4 2025 and for the full year, pivoted into one row per tenant. Restrict to tenants with at least 20 qualifying payments in 2025 total, to avoid single-payment noise (note in the report how many tenants were excluded by this threshold). Order by refund_rate_q3_pct descending, tie-break merchant_name ascending; print the top 30 rows.
      
      Check your query with the warehouse's dry_run tool, then hand it in with submit.
    • Ines calls dry_run
      WITH fx AS (
        SELECT quote_code, as_of, rate
        FROM exchange_rates
        WHERE base_code = 'EUR'
      ),
      base AS (
        SELECT
          p.tenant_id,
          p.currency_code,
          p.amount,
          p.amount_refunded,
          CAST(p.captured_at AS date) AS captured_date,
          EXTRACT(QUARTER FROM p.captured_at)::int AS q
        FROM payments p
        JOIN tenants t ON t.id = p.tenant_id
        WHERE (t.industry IS DISTINCT FROM 'Apparel & Footwear')
          AND p.status IN ('captured', 'refunded', 'partially_refunded')
          AND p.captured_at >= TIMESTAMP '2025-01-01'
          AND p.captured_at < TIMESTAMP '2026-01-01'
      ),
      converted AS (
        SELECT
          b.tenant_id,
          b.q,
          CASE WHEN b.currency_code = 'EUR' THEN b.amount ELSE b.amount / fx.rate END AS amount_eur,
          CASE WHEN b.currency_code = 'EUR' THEN b.amount_refunded ELSE b.amount_refunded / fx.rate END AS refunded_eur
        FROM base b
        LEFT JOIN fx ON fx.quote_code = b.currency_code AND fx.as_of = b.captured_date
      ),
      tenant_quarter AS (
        SELECT tenant_id, q,
               SUM(amount_eur) AS gross_eur,
               SUM(refunded_eur) AS refunded_eur,
               COUNT(*) AS cnt
        FROM converted
        GROUP BY tenant_id, q
      ),
      tenant_total AS (
        SELECT tenant_id,
               SUM(gross_eur) AS gross_eur_fy,
               SUM(refunded_eur) AS refunded_eur_fy,
               SUM(cnt) AS cnt_fy
        FROM tenant_quarter
        GROUP BY tenant_id
      ),
      qualified AS (
        SELECT tenant_id FROM tenant_total WHERE cnt_fy >= 20
      ),
      pivot AS (
        SELECT
          tt.tenant_id,
          tt.gross_eur_fy,
          tt.refunded_eur_fy,
          MAX(CASE WHEN tq.q = 1 THEN tq.gross_eur END) AS q1_gross,
          MAX(CASE WHEN tq.q = 1 THEN tq.refunded_eur END) AS q1_ref,
          MAX(CASE WHEN tq.q = 2 THEN tq.gross_eur END) AS q2_gross,
          MAX(CASE WHEN tq.q = 2 THEN tq.refunded_eur END) AS q2_ref,
          MAX(CASE WHEN tq.q = 3 THEN tq.gross_eur END) AS q3_gross,
          MAX(CASE WHEN tq.q = 3 THEN tq.refunded_eur END) AS q3_ref,
          MAX(CASE WHEN tq.q = 4 THEN tq.gross_eur END) AS q4_gross,
          MAX(CASE WHEN tq.q = 4 THEN tq.refunded_eur END) AS q4_ref
        FROM tenant_total tt
        JOIN tenant_quarter tq ON tq.tenant_id = tt.tenant_id
        WHERE tt.tenant_id IN (SELECT tenant_id FROM qualified)
        GROUP BY tt.tenant_id, tt.gross_eur_fy, tt.refunded_eur_fy
      )
      SELECT
        t.name AS merchant_name,
        t.industry AS vertical,
        ROUND(p.gross_eur_fy, 2) AS gross_captured_eur_fy2025,
        ROUND(100.0 * p.q1_ref / NULLIF(p.q1_gross, 0), 2) AS refund_rate_q1_pct,
        ROUND(100.0 * p.q2_ref / NULLIF(p.q2_gross, 0), 2) AS refund_rate_q2_pct,
        ROUND(100.0 * p.q3_ref / NULLIF(p.q3_gross, 0), 2) AS refund_rate_q3_pct,
        ROUND(100.0 * p.q4_ref / NULLIF(p.q4_gross, 0), 2) AS refund_rate_q4_pct,
        ROUND(100.0 * p.refunded_eur_fy / NULLIF(p.gross_eur_fy, 0), 2) AS refund_rate_fy2025_pct
      FROM pivot p
      JOIN tenants t ON t.id = p.tenant_id
      ORDER BY refund_rate_q3_pct DESC NULLS LAST, merchant_name ASC
      LIMIT 30
    • The warehouse answers
      STATUS: REJECTED
        - not a single SELECT statement: syntax error at or near "pivot"
    • Ines calls dry_run
      WITH fx AS (
        SELECT quote_code, as_of, rate
        FROM exchange_rates
        WHERE base_code = 'EUR'
      ),
      base AS (
        SELECT
          p.tenant_id,
          p.currency_code,
          p.amount,
          p.amount_refunded,
          CAST(p.captured_at AS date) AS captured_date,
          EXTRACT(QUARTER FROM p.captured_at)::int AS q
        FROM payments p
        JOIN tenants t ON t.id = p.tenant_id
        WHERE (t.industry IS DISTINCT FROM 'Apparel & Footwear')
          AND p.status IN ('captured', 'refunded', 'partially_refunded')
          AND p.captured_at >= TIMESTAMP '2025-01-01'
          AND p.captured_at < TIMESTAMP '2026-01-01'
      ),
      converted AS (
        SELECT
          b.tenant_id,
          b.q,
          CASE WHEN b.currency_code = 'EUR' THEN b.amount ELSE b.amount / fx.rate END AS amount_eur,
          CASE WHEN b.currency_code = 'EUR' THEN b.amount_refunded ELSE b.amount_refunded / fx.rate END AS refunded_eur
        FROM base b
        LEFT JOIN fx ON fx.quote_code = b.currency_code AND fx.as_of = b.captured_date
      ),
      tenant_quarter AS (
        SELECT tenant_id, q,
               SUM(amount_eur) AS gross_eur,
               SUM(refunded_eur) AS refunded_eur,
               COUNT(*) AS cnt
        FROM converted
        GROUP BY tenant_id, q
      ),
      tenant_total AS (
        SELECT tenant_id,
               SUM(gross_eur) AS gross_eur_fy,
               SUM(refunded_eur) AS refunded_eur_fy,
               SUM(cnt) AS cnt_fy
        FROM tenant_quarter
        GROUP BY tenant_id
      ),
      qualified AS (
        SELECT tenant_id FROM tenant_total WHERE cnt_fy >= 20
      ),
      pivoted AS (
        SELECT
          tt.tenant_id,
          tt.gross_eur_fy,
          tt.refunded_eur_fy,
          MAX(CASE WHEN tq.q = 1 THEN tq.gross_eur END) AS q1_gross,
          MAX(CASE WHEN tq.q = 1 THEN tq.refunded_eur END) AS q1_ref,
          MAX(CASE WHEN tq.q = 2 THEN tq.gross_eur END) AS q2_gross,
          MAX(CASE WHEN tq.q = 2 THEN tq.refunded_eur END) AS q2_ref,
          MAX(CASE WHEN tq.q = 3 THEN tq.gross_eur END) AS q3_gross,
          MAX(CASE WHEN tq.q = 3 THEN tq.refunded_eur END) AS q3_ref,
          MAX(CASE WHEN tq.q = 4 THEN tq.gross_eur END) AS q4_gross,
          MAX(CASE WHEN tq.q = 4 THEN tq.refunded_eur END) AS q4_ref
        FROM tenant_total tt
        JOIN tenant_quarter tq ON tq.tenant_id = tt.tenant_id
        WHERE tt.tenant_id IN (SELECT tenant_id FROM qualified)
        GROUP BY tt.tenant_id, tt.gross_eur_fy, tt.refunded_eur_fy
      )
      SELECT
        t.name AS merchant_name,
        t.industry AS vertical,
        ROUND(p.gross_eur_fy, 2) AS gross_captured_eur_fy2025,
        ROUND(100.0 * p.q1_ref / NULLIF(p.q1_gross, 0), 2) AS refund_rate_q1_pct,
        ROUND(100.0 * p.q2_ref / NULLIF(p.q2_gross, 0), 2) AS refund_rate_q2_pct,
        ROUND(100.0 * p.q3_ref / NULLIF(p.q3_gross, 0), 2) AS refund_rate_q3_pct,
        ROUND(100.0 * p.q4_ref / NULLIF(p.q4_gross, 0), 2) AS refund_rate_q4_pct,
        ROUND(100.0 * p.refunded_eur_fy / NULLIF(p.gross_eur_fy, 0), 2) AS refund_rate_fy2025_pct
      FROM pivoted p
      JOIN tenants t ON t.id = p.tenant_id
      ORDER BY refund_rate_q3_pct DESC NULLS LAST, merchant_name ASC
      LIMIT 30
    • The warehouse answers
      STATUS: COMPILES (dry run on the empty schema, no data read)
      COLUMNS: merchant_name, vertical, gross_captured_eur_fy2025, refund_rate_q1_pct, refund_rate_q2_pct, refund_rate_q3_pct, refund_rate_q4_pct, refund_rate_fy2025_pct
    • InesQuery compiles correctly with the expected 8 columns. Submitting now.
    • Ines calls submit
      WITH fx AS (
        SELECT quote_code, as_of, rate
        FROM exchange_rates
        WHERE base_code = 'EUR'
      ),
      base AS (
        SELECT
          p.tenant_id,
          p.currency_code,
          p.amount,
          p.amount_refunded,
          CAST(p.captured_at AS date) AS captured_date,
          EXTRACT(QUARTER FROM p.captured_at)::int AS q
        FROM payments p
        JOIN tenants t ON t.id = p.tenant_id
        WHERE (t.industry IS DISTINCT FROM 'Apparel & Footwear')
          AND p.status IN ('captured', 'refunded', 'partially_refunded')
          AND p.captured_at >= TIMESTAMP '2025-01-01'
          AND p.captured_at < TIMESTAMP '2026-01-01'
      ),
      converted AS (
        SELECT
          b.tenant_id,
          b.q,
          CASE WHEN b.currency_code = 'EUR' THEN b.amount ELSE b.amount / fx.rate END AS amount_eur,
          CASE WHEN b.currency_code = 'EUR' THEN b.amount_refunded ELSE b.amount_refunded / fx.rate END AS refunded_eur
        FROM base b
        LEFT JOIN fx ON fx.quote_code = b.currency_code AND fx.as_of = b.captured_date
      ),
      tenant_quarter AS (
        SELECT tenant_id, q,
               SUM(amount_eur) AS gross_eur,
               SUM(refunded_eur) AS refunded_eur,
               COUNT(*) AS cnt
        FROM converted
        GROUP BY tenant_id, q
      ),
      tenant_total AS (
        SELECT tenant_id,
               SUM(gross_eur) AS gross_eur_fy,
               SUM(refunded_eur) AS refunded_eur_fy,
               SUM(cnt) AS cnt_fy
        FROM tenant_quarter
        GROUP BY tenant_id
      ),
      qualified AS (
        SELECT tenant_id FROM tenant_total WHERE cnt_fy >= 20
      ),
      pivoted AS (
        SELECT
          tt.tenant_id,
          tt.gross_eur_fy,
          tt.refunded_eur_fy,
          MAX(CASE WHEN tq.q = 1 THEN tq.gross_eur END) AS q1_gross,
          MAX(CASE WHEN tq.q = 1 THEN tq.refunded_eur END) AS q1_ref,
          MAX(CASE WHEN tq.q = 2 THEN tq.gross_eur END) AS q2_gross,
          MAX(CASE WHEN tq.q = 2 THEN tq.refunded_eur END) AS q2_ref,
          MAX(CASE WHEN tq.q = 3 THEN tq.gross_eur END) AS q3_gross,
          MAX(CASE WHEN tq.q = 3 THEN tq.refunded_eur END) AS q3_ref,
          MAX(CASE WHEN tq.q = 4 THEN tq.gross_eur END) AS q4_gross,
          MAX(CASE WHEN tq.q = 4 THEN tq.refunded_eur END) AS q4_ref
        FROM tenant_total tt
        JOIN tenant_quarter tq ON tq.tenant_id = tt.tenant_id
        WHERE tt.tenant_id IN (SELECT tenant_id FROM qualified)
        GROUP BY tt.tenant_id, tt.gross_eur_fy, tt.refunded_eur_fy
      )
      SELECT
        t.name AS merchant_name,
        t.industry AS vertical,
        ROUND(p.gross_eur_fy, 2) AS gross_captured_eur_fy2025,
        ROUND(100.0 * p.q1_ref / NULLIF(p.q1_gross, 0), 2) AS refund_rate_q1_pct,
        ROUND(100.0 * p.q2_ref / NULLIF(p.q2_gross, 0), 2) AS refund_rate_q2_pct,
        ROUND(100.0 * p.q3_ref / NULLIF(p.q3_gross, 0), 2) AS refund_rate_q3_pct,
        ROUND(100.0 * p.q4_ref / NULLIF(p.q4_gross, 0), 2) AS refund_rate_q4_pct,
        ROUND(100.0 * p.refunded_eur_fy / NULLIF(p.gross_eur_fy, 0), 2) AS refund_rate_fy2025_pct
      FROM pivoted p
      JOIN tenants t ON t.id = p.tenant_id
      ORDER BY refund_rate_q3_pct DESC NULLS LAST, merchant_name ASC
      LIMIT 30
    • The warehouse answers
      Submitted to tonight's batch. Your work on this request is done.
    • InesSubmitted. Summary of what the query does: - Filters `payments` to 2025 captures with status in (`captured`, `refunded`, `partially_refunded`), joined to `tenants`, excluding `industry = 'Apparel & Footwear'`. - Converts `amount` and `amount_refunded` to EUR per row using the day's `exchange_rates` (base `EUR`), matching on `captured_at`'s date. - Aggregates gross and refunded EUR per tenant per quarter, then totals for the year. - Keeps only tenants with ≥20 qualifying payments in 2025. - Pivots quarters into columns and computes refund-rate % (refunded/gross) for Q1–Q4 and FY2025. - Orders by Q3 refund rate descending (tie-break by merchant name), returns top 30 rows, one row per merchant. Note sent to the analyst: the excluded-tenant count from the ≥20-payment threshold isn't representable at this per-tenant grain (would need a separate single-row report), and quarters with zero gross for a tenant show a null rate rather than a divide-by-zero error.