Vol. I · A Postgres HandbookTwelve chapters · · 756 queries

The Query & the Schema

A reading-room reference for writing PostgreSQL by hand — selects to window functions, with the schema in plain view.

IntermediatePerformance & Indexes

Create a multi-column (composite) index

SQL

CREATE INDEX idx_emp_dept_salary 
ON employees (dept_id, salary DESC);

Tested against PostgreSQL 16

Note

“Column order matters! This index is highly optimized for queries filtering on dept_id and sorting by salary.