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master
examples/sql/sql-8821-010/main.sql
42 строки
890 B
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Code migration pack
09 июн 2026, 01:41
09 июн 2026, 01:41
cebc284
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-- Анализ плана выполнения в различных СУБД -- Oracle EXPLAIN PLAN FOR SELECT /*+ PARALLEL(employees 4) */ department_id, COUNT(*) FROM employees GROUP BY department_id; SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY); -- PostgreSQL EXPLAIN ANALYZE SELECT /*+ HashJoin(e d) */ d.department_name, COUNT(e.employee_id) FROM employees e JOIN departments d ON e.department_id = d.department_id GROUP BY d.department_name; -- SQL Server SET SHOWPLAN_ALL ON; GO SELECT d.DepartmentName, COUNT(e.EmployeeID) FROM Employees e JOIN Departments d ON e.DepartmentID = d.DepartmentID GROUP BY d.DepartmentName; SET SHOWPLAN_ALL OFF; GO -- MySQL EXPLAIN FORMAT=JSON SELECT /*+ BKA(d) */ d.department_name, COUNT(e.employee_id) FROM employees e JOIN departments d ON e.department_id = d.department_id GROUP BY d.department_name;