Question

我正在尝试构建SQL查询但我收到以下错误：

#1054 - Unknown column 'r.id' in 'where clause'

这是我的疑问：

SELECT *, COUNT(id) AS result_count 
    FROM rate_clicks AS rc 
    WHERE click_type = 'details' 
    AND created_at > 1463517035 
    AND rate <= (SELECT rate 
        FROM rates AS r 
        WHERE r.id = rc.rate_id) 
    GROUP BY rate_id 
    ORDER BY result_count DESC LIMIT 5

我之前没有使用过子查询，所以我认为这是我失败的地方。非常感谢您的帮助！

Answer 1

MySQL在子查询中不接受父级的别名。你应该加入：

SELECT *, COUNT(id) AS `result_count` 
FROM `rate_clicks` AS `rc` 
WHERE `click_type` = 'details' AND `created_at` > 1463517035 
AND `rate` <= (SELECT `rate` FROM `rates` AS `r` 
               inner join `rate_clicks` as rc1  `r.id`=`rc1.rate_id`) 
GROUP BY `rate_id` 
ORDER BY `result_count` DESC LIMIT 5

Answer 2

我发布它作为答案。你使用了错误的反引号

改变这个：

WHERE `r.id`=`rc.rate_id`

到

WHERE `r`.`id`=`rc`.`rate_id`

<强>样品

MariaDB [bb]> SELECT * FROM useindex i WHERE `i.num1`= 999 LIMIT 10;
ERROR 1054 (42S22): Unknown column 'i.num1' in 'where clause'
MariaDB [bb]>
MariaDB [bb]> SELECT * FROM useindex i WHERE `i`.`num1`= 999 LIMIT 10;
+-------+------+------+
| id    | num1 | num2 |
+-------+------+------+
|   511 |  999 |  686 |
|  1878 |  999 |  687 |
|  3241 |  999 |  686 |
|  3245 |  999 |  688 |
|  4608 |  999 |  687 |
|  5971 |  999 |  685 |
|  5975 |  999 |  687 |
|  7338 |  999 |  686 |
|  8705 |  999 |  687 |
| 10068 |  999 |  686 |
+-------+------+------+
10 rows in set (0.00 sec)

MariaDB [bb]>

MYSQL：WHERE子句中的子查询帮助

2 个答案: