Oracle集合运算符

来源：互联网发布：python教程 snmp 编辑：程序博客网时间：2024/05/18 03:14

  集合运算符：UNION/UNION ALL 并集，INTERSECT 交集，MINUS 差集一、union求并集，公共部分只有包含一次例：求emp表ename中含’A‘或含有‘M’SQL> select * from emp where ename like '%A%'  2  union  3  select * from emp where ename like '%M%';二、union all求集并，公共部分只有包含二次例：求emp表ename中含’A‘或含有‘M’SQL> select * from emp where ename like '%A%'  2  union all  3  select * from emp where ename like '%M%';三、intersect求交集，只有包含公共部分例：求emp表ename中即含’A‘又含有‘M’SQL> select * from emp where ename like '%A%'     intersect     select * from emp where ename like '%M%';四、minus求差集，求集合A去除集合A和集合B的交集例：求emp表sal从700到1200SQL>select * from emp where sal between 700 and 1300    minus    select * from emp where sal between 1200 and 1400;