[英]SQL query error unknown column in SELECT + JOIN +
This is my SQL code (using phpmyadmin simulator) : 这是我的SQL代码(使用phpmyadmin模拟器):
SELECT user_activity.user_ip,user_activity.id,user_activity.post_id , posts.id
FROM user_activity,users
INNER JOIN posts ON user_activity.post_id = posts.id
WHERE user_activity.user_id = users.id and users.forgen_note = 'test note';
And it respons an error: 它响应一个错误:
MySQL said: Documentation
#1054 - Unknown column 'user_activity_now.stream_id' in 'on clause'
How can I fix it please? 我该如何解决?
Don't mix join syntax: 不要混合联接语法:
SELECT user_activity.user_ip,user_activity.id,user_activity.post_id, posts.id
FROM user_activity
INNER JOIN users ON user_activity.user_id = users.id
INNER JOIN posts ON user_activity.post_id = posts.id
WHERE users.forgen_note = 'test note';
Generally you should avoid using comma joins. 通常,您应该避免使用逗号联接。 It's harder to read and is less expressive overall about what you're doing. 关于您正在做的事情,阅读起来比较困难,表达能力也较差。
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