qq_39131467的博客

原创 SQL语言基础

sql语言基础一. 基础select子句select * from emp; //查询emp表格所有内容select empno, ename,sal*12 as nianxin from emp; //查询部门，姓名，年薪select * from emp where (job='CLERK' or job='SALESMAN') and sal>1250; //or和and的合用select distinct ename, job from emp; //查询所