Postgres Table Primary Keys: retrieves the primary keys for the user tables in the database (or filter with additional WHERE criteria). Includes composite primary key columns

gistfile1.sql

SELECT 
    ctu.table_name table_name, 
    ctu.constraint_name key_name, 
    ccu.column_name
FROM information_schema.table_constraints tc 
  INNER JOIN information_schema.constraint_table_usage ctu
    ON ctu.constraint_name = tc.constraint_name 
  INNER JOIN information_schema.constraint_column_usage ccu 
    ON ccu.constraint_name = ctu.constraint_name
WHERE tc.constraint_type = 'PRIMARY KEY' 
  AND tc.table_schema NOT IN ('pg_catalog', 'information_schema')
ORDER BY ctu, key_name, column_name;