mysql - MySQL用不同的列查找查询两个表

Question

如何使这种语法有效：

SELECT * 
FROM
  uploads,
  audienceuploadassociation 
WHERE 
  uploads.member_id = '1'
  AND uploads.member_school_id='1' 
  AND subject = 'Maths' 
  AND uploads.upload_id = audienceuploadassociation.upload_id 
  AND topic = 'Integers' 
  AND year IN(7, 8, 9) 
  AND audienceuploadassociation.audiencename LIKE (Parents, Teachers, Community)

Answer 1

你的LIKE条款有问题。我怀疑您打算改用一个IN()子句：

AND audienceuploadassociation.audiencename IN ('Parents', 'Teachers', 'Community')

如果您尝试将部分字符串与 匹配LIKE，则需要将OR它们放在一个()组中，如下所示：

AND (
  audienceuploadassociation.audiencename LIKE 'Parents%'
  OR audienceuploadassociation.audiencename LIKE 'Teachers%'
  OR audienceuploadassociation.audiencename LIKE 'Community%'
)

另请注意，您使用的隐式连接语法（逗号分隔的表）已被弃用，取而代之的是显式的JOIN.

SELECT
  uploads.*,
  audienceuploadassociation.*
FROM
  /* Explicit JOIN  with ON clause */
  uploads
  JOIN audienceuploadassociation ON uploads.upload_id = audienceuploadassociation.upload_id 
WHERE 
  uploads.member_id = '1'
  AND uploads.member_school_id='1' 
  AND subject = 'Maths' 
  AND topic = 'Integers' 
  AND year IN(7, 8, 9) 
  AND audienceuploadassociation.audiencename IN ('Parents', 'Teachers', 'Community')

最后，我建议明确命名您想要的列而不是这样做SELECT *，因此您可以按确定的顺序获取它们，并防止稍后在此查询中添加您不需要的其他列：

SELECT 
  uploads.upload_id,
  uploads.other_column,
  uploads.topic,
  audienceuploadassociation.audiencename,
  ...
  ...

Answer 2

这行得通吗？

SELECT * 
FROM
  uploads,
  audienceuploadassociation 
WHERE 
  uploads.member_id = '1'
  AND uploads.member_school_id='1' 
  AND subject = 'Maths' 
  AND uploads.upload_id = audienceuploadassociation.upload_id 
  AND topic = 'Integers' 
  AND year IN(7, 8, 9) 
  AND audienceuploadassociation.audiencename IN ('Parents', 'Teachers', 'Community');