81,092
社区成员
发帖
与我相关
我的任务
分享
Select id, name, price
From (
Select * From table1
Union
Select * From table2
)
Order By price Desc
Where rownum <= 5
性能改进是:
Select id, name, price
From (
Select * From table1 Order By price Desc Where rownum <= 5
Union
Select * From table2 Order By price Desc Where rownum <= 5
)
Order By price Desc
Where rownum <= 5