Question

此查询出现SQL错误

错误号：1064
    您的SQL语法有误；查看与您的MySQL服务器版本相对应的手册，以在'*）附近使用正确的语法
   来自`cast_gallery` q
   在q.all_media_id = r.id上加入`all_media` r
   在第1行的q.pa'

SELECT `cast_name`, `cast_slug`, (SELECT count(q.*)
 FROM `cast_gallery` q
 JOIN `all_media` r on q.all_media_id=r.id
 WHERE q.parent = `casts`.`id` AND r.approved=1) as image_gallery, `active`, `view`, `checked`, `sex`, `id`
FROM (`casts`)
ORDER BY `cast_name` asc
LIMIT 10

如何解决？

Answer 1

要计算总行数，我们使用COUNT(*)，而不是Count(q.*)。另外，casts子句中的From周围也不需要括号。

SELECT `cast_name`, 
       `cast_slug`, 
       (SELECT count(*)
        FROM `cast_gallery` q
        JOIN `all_media` r on q.all_media_id=r.id
        WHERE q.parent = `casts`.`id` AND 
              r.approved=1) as image_gallery, 
      `active`, 
      `view`, 
      `checked`, 
      `sex`, 
      `id`
FROM `casts`
ORDER BY `cast_name` asc
LIMIT 10

其他信息：

COUNT(...)用于计算非NULL 值的数量；但是COUNT(*)将计算检索到的行总数，无论它们是否包含NULL值。

Answer 2

尝试仅将count(q.*)更改为count(*)

Answer 3

计数语法不正确。如果要在子查询中查找行数，可以使用count（*）。有关更多说明，请参阅http://www-db.deis.unibo.it/courses/TW/DOCS/w3schools/sql/sql_func_count.asp.html。

SELECT `cast_name`, `cast_slug`, (SELECT count(*)
FROM `cast_gallery` q
JOIN `all_media` r on q.all_media_id=r.id
WHERE q.parent = `casts`.`id` AND r.approved=1) as image_gallery, `active`, 
`view`, `checked`, `sex`, `id`
FROM (`casts`)
ORDER BY `cast_name` asc
LIMIT 10

应该工作

Answer 4

您可以尝试使用q.all_media_id代替count（q。*）

SELECT `cast_name`, `cast_slug`, (SELECT count(q.all_media_id)
 FROM `cast_gallery` q
 JOIN `all_media` r on q.all_media_id=r.id
 WHERE q.parent = `casts`.`id` AND r.approved=1) as image_gallery, `active`, `view`, `checked`, `sex`, `id`
FROM (`casts`)
ORDER BY `cast_name` asc
LIMIT 10

选择语句中的子查询返回SQL错误

4 个答案: