sql - "HAVING ... GROUP BY"和 "GROUP BY ... HAVING"之间的区别

Question

我的表 MYTABLE 有 2 列:A 和 B

我有以下代码片段:

SELECT MYTABLE.A FROM MYTABLE 
    HAVING SUM(MYTABLE.B) > 100
    GROUP BY MYTABLE.A

和

SELECT MYTABLE.A FROM MYTABLE 
    GROUP BY MYTABLE.A
    HAVING SUM(MYTABLE.B) > 100

是一样的吗？这两个代码是否有可能返回不同的结果集？

提前谢谢

Answer 1

根据记录，没有区别。人们只是习惯在 GROUP BY 之后看到 HAVING。

http://docs.oracle.com/cd/B28359_01/server.111/b28286/statements_10002.htm#SQLRF20040

Specify GROUP BY and HAVING after the where_clause and hierarchical_query_clause. If you specify both GROUP BY and HAVING, then they can appear in either order.

http://sqlfiddle.com/#!4/66e33/1