Subquery in HAVING
Subquery in HAVING is a SQL statement in the Subqueries category. A subquery used in the HAVING clause to filter groups based on aggregated results from another query. The syntax is SELECT column, agg_func(col) FROM table GROUP BY column HAVING agg_func(col) operator (subquery);. It returns filtered groups. A typical example: SELECT department, AVG(salary) AS avg_salary FROM employees GROUP BY department HAVING AVG(salary) > (SELECT AVG(salary) * 1.1 FROM employees); -- Departments where average salary is >110% of company average A close relative is Scalar Subquery, which a subquery that returns a single value (one row, one column). Can be used in SELECT, WHERE, HAVING clauses. A close relative is Correlated Subquery, which a subquery that references columns from the outer query. Evaluated for each row of the outer query. A close relative is EXISTS, which returns TRUE if the subquery returns at least one row. Often faster than IN for large datasets.