插入数据
-- 单条插入
INSERT INTO emp(employee_id,last_name,hire_date,salary)
VALUES(200,'LQF',SYSDATE,10000)
-- 从已有表中筛选数据插入
INSERT INTO emp(employee_id,last_name,hire_date,salary)
SELECT employee_id,last_name,hire_date,salary
FROM employees e
WHERE e.department_id = 80更新
UPDATE employees e
SET job_id = (SELECT e1.job_idFROM employees e1WHERE e1.employee_id = 205),
e.salary = (SELECT e2.salaryFROM employees e2WHERE e2.employee_id = 205 )
WHERE e.employee_id = 206;
事务
commit：提交
rollback：回滚
savepoint：保存当前数据库处于点
-- 删除一条记录
delete from employees where employee_id = 206;
-- 保存当前的状态A
savepoint A;
--再删除一条记录
delete from employees where employee_id = 202;
-- 保存当前的状态B
savepoint B;
--当回滚到点A时记录202是存在的
rollback to savepoint A;
--rollback会直接回到最初的202和206都存在的状态
rollback;