WHERE vs HAVING
WHERE filters rows before grouping; HAVING filters groups after aggregation.
WHERE
Use it when
Use WHERE for Status=Open before GROUP BY.
HAVING
Use it when
Use HAVING for COUNT(*)>5 after GROUP BY.
Decision rule
Choose the option that matches the real requirement, data size, maintainability needs and compatibility constraints. Avoid selecting a technique only because it is familiar.
Need clarity?Prefer the simpler option that expresses the business rule directly.
Verify before scaling
Run both approaches on a small known dataset if the difference affects financial, inventory or operational decisions. Equivalent-looking techniques can behave differently with duplicates, blanks, NULL values or version constraints.