MySQL显示零结果时有一些？

Question

我有一个如下表:

id | description | db_url | form_url | user | projectid

2 | nailbar | TSF/nailbar/index.php | TSF/nailbar/upload.php | test_user | 2

1 | jewellery | TSF/jewellery/index.php | TSF/jewellery/upload.php | test_user | 1

1 | jewellery | TSF/jewellery/index.php | TSF/jewellery/upload.php | test_user2 | 1

3 | locker | TSF/locker/index.php | TSF/locker/upload.php | test_user | 3

当我执行以下查询时，没有任何结果:

SELECT * 
FROM projects
JOIN member_projects ON member_projects.projectid = projects.id
WHERE user =  'test_user'
AND db_url =  'TSF/locker/index.php'
LIMIT 0 , 30

显然存在匹配，所以我不明白为什么它会得出零结果？

Answer 1

当字符串的开头或结尾有额外的字符时，通常会发生这种情况。最有可能的罪魁祸首是网址。您可以尝试:

SELECT * 
FROM projects p JOIN
     member_projects mp
     ON mp.projectid = p.id
WHERE user =  'test_user' AND
      trim(db_url) =  'TSF/locker/index.php'
LIMIT 0 , 30;

如果上述方法不起作用，您还可以查找“包含”而不是完整匹配项:

SELECT * 
FROM projects p JOIN
     member_projects mp
     ON mp.projectid = p.id
WHERE user =  'test_user' AND
      db_url like '%TSF/locker/index.php%'
LIMIT 0 , 30;