Claude SQL Query Prompt with a Fictional Schema and Expected Rows

Draft a SQL query for analysts and developers in Claude: built from the schema you give, plus a check of the result on a small test fixture.

By Genius ForgesUpdated Oct 10, 2026

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DialectQuestionSchema

Your prompt

Act as a Senior Data Engineer and Database Administrator. I need you to generate an optimized SQL query based on my natural language request.
Context:
Dialect: {{dialect}}
My Request: {{question}}
Database Schema:
SQL


{{schema}}


Your Task:
Please provide the solution in 3 distinct sections.
Section 1: The Optimized Query
Write the SQL query to answer my request.
Use modern SQL best practices (CTEs over subqueries where appropriate).
Use proper indentation and capitalization (e.g., SELECT, WHERE).
Handle potential edge cases (e.g., NULL values or division by zero).
Section 2: The Logic Breakdown
Briefly explain how the query works in plain English.
Explain the logic behind any Joins, Grouping, or Window Functions used.
Section 3: Performance Check
Recommend one specific Index that would make this query run faster, explaining which columns should be indexed and why.
Output everything in clean Markdown.

Preserve provided facts. Identify missing evidence and assumptions. Do not promise rankings, replies, hiring, perfect fidelity or measured performance without supporting tests.

3 inputs still blank. Empty inputs stay as placeholders when copied.

Use it on

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Example result

Fictional SQLite schema: expenses(category TEXT, amount REAL). Rows: Supplies 12.5; Travel 20; Supplies 7.5. Query: SELECT SUM(amount) AS total FROM expenses WHERE category = 'Supplies'; Expected: one row, total 20. For a missing category SUM returns NULL; use COALESCE only if the requirement explicitly calls for zero. Run read-only fixture tests before adapting to real data.

Illustrative example; results vary by input and platform.

How to use this prompt

1Supply the SQL dialect, table columns and exact question; use fictional data for the first test.
2Check joins, NULL handling and expected totals in a disposable database. Do not execute generated writes against production.
3Inspect the query plan before recommending an index; compare the result to an independently calculated expected answer.

Tips & limitations

Editorial example, not a recorded platform test. Use the current model available in your account; no model settings are recommended from an unobserved run.