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Oct 4, 2026 · Databases

Why SQL's Written Order ≠ Execution Order: The Hidden Logic Behind Query Processing

This article explains the logical execution order of SQL clauses (FROM, WHERE, GROUP BY, HAVING, SELECT, ORDER BY, LIMIT), why SELECT aliases aren't visible in WHERE, how HAVING differs from WHERE, JOIN/ON placement, LEFT JOIN pitfalls, and how to verify with EXPLAIN, distinguishing logical vs. physical execution order.