Reviewed by Aditya Kumar · Last reviewed 2026-03-24
**Simple:** CASE col WHEN v1 THEN r1 ... **Searched:** CASE WHEN cond1 THEN r1 WHEN cond2 THEN r2 ELSE r3 END. Use in SELECT, WHERE, ORDER BY, GROUP BY. SELECT name, CASE WHEN score>=90 THEN 'A' WHEN score>=80 THEN 'B' ELSE 'C' END AS grade FROM students;
Simple: CASE col WHEN v1 THEN r1 ... Searched: CASE WHEN cond1 THEN r1 WHEN cond2 THEN r2 ELSE r3 END. Use in SELECT, WHERE, ORDER BY, GROUP BY.
SELECT name, CASE WHEN score>=90 THEN 'A' WHEN score>=80 THEN 'B' ELSE 'C' END AS grade FROM students;
Red Flag: No ELSE (unexpected NULL). Pro-Move: 'We use for bucketing, decoding flags, custom sort—ELSE always explicit.'
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