Workarounds & Engine Limits

Every SQL engine has limitations around window functions. Understanding these constraints and their workarounds prevents hours of debugging cryptic error messages. The most common issues involve where window functions can appear in a query, missing syntax features, and ordering guarantees. Placement Restrictions SQL's evaluation order determines where window functions can and cannot appear. These restrictions apply across all SQL engines. Window Functions vs WHERE Window Functions vs HAVING Repeating OVER Clauses Advanced Window Techniques Beyond the basic restrictions, several advanced techniques and ordering behaviors require careful attention. ARRAY_AGG with OVER Window Function Order ORDER BY in Subqueries Another common source of unexpected NULLs in window function results involves fr