Question

此处的mySQL语句尝试按年打印总发票金额。

> select YEAR(I.INV_DATE), SUM(LINE_UNITS * LINE_PRICE) as total    from
> INVOICE I, LINE L     where I.INV_NUMBER = L.INV_NUMBER   group by 1

但如果我添加喜欢（仅打印年份大于500的那些）

> select YEAR(I.INV_DATE), SUM(LINE_UNITS * LINE_PRICE) as total    from
> INVOICE I, LINE L     where I.INV_NUMBER = L.INV_NUMBER   group by 1
>         where total > 500

给我错误消息：语法错误

我做错了什么？谢谢！

Answer 1

使用HAVING代替WHERE

SELECT....
FROM ...
GROUP BY ...
HAVING SUM(LINE_UNITS * LINE_PRICE) > 500

或者你可以将它包装在像这样的子查询中，

SELECT *
FROM
(
    SELECT  YEAR(I.INV_DATE), SUM(LINE_UNITS * LINE_PRICE) as total
    FROM    INVOICE I, LINE L
    WHERE   I.INV_NUMBER = L.INV_NUMBER   
    GROUP   BY 1
) a
WHERE total > 500

Answer 2

SELECT YEAR(I.INV_DATE), SUM(LINE_UNITS * LINE_PRICE) as total 
FROM INVOICE I, LINE L     
WHERE  I.INV_NUMBER = L.INV_NUMBER   
GROUP BY 1
HAVING total > 500

参见http://dev.mysql.com/doc/refman/5.0/en/group-by-extensions.html 您需要将HAVING与GROUP BY

一起使用

“WHERE”在mySQL语句中不起作用

2 个答案: