1 from
2, join ..on
3,where,
4,group by
5 having ,
6,select
7,distinct,
8,order by
例如,查詢平均工資高于8000的部門的最高和最低 工資
select max(sal),min(sal),depto from emp group by depto having avg(sal) >8000
先 from emp表,有關聯 在關聯(join..on) ,然後 where條件,接着 group by, having, select ,