This page is a quick reference checkpoint for COUNT OVER in ORACLE: behavior, syntax rules, edge cases, and a minimal example; plus the official vendor documentation.
COUNT OVER returns the number of rows in the window frame.
COUNT never returns null. DISTINCT analytic use restricts analytic_clause to PARTITION BY only.
If this behavior feels unintuitive, the tutorial below explains the underlying pattern step-by-step.
Syntax: COUNT(expr) OVER (analytic_clause). COUNT(DISTINCT expr) analytic allows only PARTITION BY; ORDER BY and window frames not allowed.
SELECT last_name, salary, COUNT() OVER (ORDER BY salary RANGE BETWEEN 50 PRECEDING AND 150 FOLLOWING) AS mov_count FROM employees;
If you came here to confirm syntax, you’re done. If you came here to get better at window functions, choose your next step.
COUNT OVER is part of a bigger window-function pattern. If you want the “why”, start here: Aggregate Window Functions
Reading docs is useful. Writing the query correctly under pressure is the skill.
For the authoritative spec, use the vendor docs. This page is the fast “sanity check”.
View ORACLE Documentation →Looking for more functions across all SQL dialects? Visit the full SQL Dialects & Window Functions Documentation.