Question

我有2个工作的MYSQL语句，我想合并到1个查询中：

来自mysql select statement with unique and maximum selects?我有：

$sql="SELECT field_a, max(dup_number) as dup FROM table1 GROUP BY field_a"

我的第二个问题是：

$sql="where contacts=0 ORDER BY date LIMIT 3"

所以一组记录看起来像是：

ID     FIELD A     DUP_NUMBER  CONTACTS 
1       text1        0           1        --
2       text2        0           3        --
3       text2        1           3         --
4       text2        2           3        --
5       text3        0           2        --

我想出了：

SELECT *
FROM `table1 `
where max(`DUP_NUMBER `) as dup  and `CONTACTS`=1
GROUP BY `FIELD_A`
ORDER BY date
LIMIT 3

当我在phpmyadmin中测试时，我得到了

#1064 - You have an error in your SQL syntax.

有人能告诉我如何正确地重写这个吗？

提前致谢，

比尔

Answer 1

试试这个。

SELECT *, max(DUP_NUMBER) as dup FROM table1 where  CONTACTS=1 GROUP BY FIELD_A ORDER BY date LIMIT 3

Answer 2

问题在这里：

where max(`DUP_NUMBER `) as dup  and `CONTACTS`=1
                         ^^^^^^

你不能在where子句中使用别名，只能在字段列表中，例如：

SELECT max(DUP_NUMBER) as dup
HAVING dup=???

是你如何使用它。

如何合并这些mysql语句

2 个答案: