SQL: data reasoning to production

The course, in order

Open a unit in the map to inspect its activities. Reading, guided completion, independent work and review remain distinct evidence.

1. A cursor excludes the last seen identity

   Exclude the last seen identity and return the next bounded page in a declared deterministic order.

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2. Bind a lookup and select a nonoverlapping time period

   Keep a searched value out of SQL syntax by binding it through a fixed query rather than interpolating its spelling.

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3. Search a literal fragment containing LIKE metacharacters

   Escape LIKE metacharacters so a searched fragment is literal data while retaining the intended surrounding wildcard search.

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4. Filter before projecting a stable result

   Filter strictly positive scores before projecting IDs, excluding unknown scores and ordering the accepted rows.

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5. Choose one canonical ingestion for each event identity

   Select exactly one canonical ingestion per event with a deterministic newest-row and identity tie policy.

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6. Reject invalid stored quantities while allowing lossless SQLite coercion

   Enforce stored quantity constraints while accepting SQLite’s declared lossless conversion into a STRICT integer column.

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7. Preserve a blank note while labeling missing data

   Replace only SQL NULL with the requested label, preserving empty text, spaces and other present content.

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8. Report exact whole batches and remaining units

   Compute whole batches and remaining units under integer division, retaining the declared zero-divisor result.

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9. Nothing is not zero, and nothing does not equal itself

   Distinguish row count, known-value count and missing count without treating a stored zero as missing.

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10. Keep every eligibility branch behind its required guard

    Place the enabled guard around the entire admin-or-score condition so no OR branch can bypass it.

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11. Keeping every row and summarizing anyway

    Keep each detail row while computing region-local running totals and the declared tie-aware rank.

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12. Aggregate the qualifying values in each group

    Preserve every observed group while selecting positive contributions inside its aggregate, including groups totaling zero.

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13. A grouped relation can require every named capability

    Require both named capabilities using distinct qualifying grants rather than duplicate or unrelated permission counts.

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14. WHERE filters rows, HAVING filters groups

    Filter qualifying orders before grouping, then apply the separate aggregate threshold to the resulting groups.

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15. Preserve empty teams while filtering each aggregate independently

    Preserve empty parent teams and apply each metric’s eligibility rule inside its own aggregate.

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16. The CASE that must ask about NULL first

    Label missing scores explicitly and apply inclusive grade thresholds in descending order.

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17. Name the middle step

    Name team-grain totals in a CTE and compare against their average rather than the average underlying expense.

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18. Null replacement must preserve empty text

    Substitute the missing-team label only for NULL while preserving present empty text and stable row order.

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19. The predicate the index can actually see

    Express a month as a half-open range on the indexed date column and inspect the actual SQLite access plan.

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20. Commit the whole command batch and its delivery intent together

    Commit every valid account adjustment and its immutable delivery intent in one owned transaction, rolling the whole batch back on rejection.

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