摘要:
set linesize ;set pagesize;distinct 去重复:select distinct job from emp;select '姓名:'||name from emp; concat('name:',ename) 在姓名前面加上 姓名:查询不为空 is not nulland 并且not 取反sal between 1500 and 3000; 工资大于等于1500小于等于3000日期只能用 between 查询几个的数据:empon=1111 or empon=22222..... empon in(1111,2222,2222)en 阅读全文