SQL
语句如下:DISTINCT
关键字来实现SELECT DISTINCT 字段 FROM ......;
SELECT job FROM t_emp;
SELECT DISTINCT job FROM t_emp;
DISTINCT
的 SELECT
子句中只能查询一列数据,如果查询多列,去除重复记录就会失效。DISTINCT
关键字只能在 SELECT
子句中使用一次SELECT DISTINCT job FROM t_emp;
SELECT DISTINCT job,ename FROM t_emp;
SELECT DISTINCT job,DISTINCT ename FROM t_emp;
SELECT job,DISTINCT ename FROM t_emp;