Oracle集合運算子__Oracle

  集合運算子：UNION/UNION ALL 並集，INTERSECT 交集，MINUS 差集一、union求並集，公用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求集並，公用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，只有包含公用部分例：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從700到1200SQL>select * from emp where sal between 700 and 1300    minus    select * from emp where sal between 1200 and 1400;