Oracle 中的 Merge 语句

Merge Statement Demo

MERGE <hint> INTO <table_name> USING <table_view_or_query> ON (<condition>) WHEN MATCHED THEN <update_clause> DELETE <where_clause> WHEN NOT MATCHED THEN <insert_clause> [LOG ERRORS <log_errors_clause> <reject limit <integer | unlimited>];

CREATE TABLE employee ( employee_id NUMBER(5), first_name  VARCHAR2(20), last_name   VARCHAR2(20), dept_no     NUMBER(2), salary      NUMBER(10)); INSERT INTO employee VALUES (1, 'Dan', 'Morgan', 10, 100000); INSERT INTO employee VALUES (2, 'Jack', 'Cline', 20, 100000); INSERT INTO employee VALUES (3, 'Helen', 'Lofstrom', 20, 50000); INSERT INTO employee VALUES (4, 'Jackie', 'Stough', 20, 40000); INSERT INTO employee VALUES (5, 'Richard', 'Foote', 20, 70000); INSERT INTO employee VALUES (6, 'Joe', 'Johnson', 20, 30000); INSERT INTO employee VALUES (7, 'Clark', 'Urling', 20, 90000); CREATE TABLE bonuses ( employee_id NUMBER, bonus NUMBER DEFAULT 100); INSERT INTO bonuses (employee_id) VALUES (1); INSERT INTO bonuses (employee_id) VALUES (2); INSERT INTO bonuses (employee_id) VALUES (4); INSERT INTO bonuses (employee_id) VALUES (6); INSERT INTO bonuses (employee_id) VALUES (7); COMMIT; SELECT * FROM employee; SELECT * FROM bonuses; MERGE INTO bonuses b USING (   SELECT employee_id, salary, dept_no   FROM employee   WHERE dept_no =20) e ON (b.employee_id = e.employee_id) WHEN MATCHED THEN   UPDATE SET b.bonus = e.salary * 0.1   DELETE WHERE (e.salary < 40000) WHEN NOT MATCHED THEN   INSERT (b.employee_id, b.bonus)   VALUES (e.employee_id, e.salary * 0.05)   WHERE (e.salary > 40000); SELECT * FROM bonuses;