MySQL 左连接/WHERE
我将我的地址簿加入到我的电子邮件表中，如下所示：
SELECT * FROM messages m
LEFT JOIN addr_book a ON
m.to_msg LIKE a.h_email
OR m.to_msg LIKE a.bill_email
OR m.to_msg LIKE a.b_email
OR m.to_msg LIKE a.w_email
OR m.to_msg LIKE a.other_email
OR m.from_msg LIKE a.h_email
OR m.from_msg LIKE a.bill_email
OR m.from_msg LIKE a.b_email
OR m.from_msg LIKE a.w_email
OR m.from_msg LIKE a.other_email
OR m.cc_msg LIKE a.h_email
OR m.cc_msg LIKE a.bill_email
OR m.cc_msg LIKE a.b_email
OR m.cc_msg LIKE a.w_email
OR m.cc_msg LIKE a.other_email
OR m.bcc_msg LIKE a.h_email
OR m.bcc_msg LIKE a.bill_email
OR m.bcc_msg LIKE a.b_email
OR m.bcc_msg LIKE a.w_email
OR m.bcc_msg LIKE a.other_email
是它会获取所有内容，因为某些联系人没有电子邮件，并且会加入没有 cc_msg='' 或 bcc_msg='' 的电子邮件
问题 我可以在列上左连接一个表，其中该列类似于“@”？
我尝试了一些诸如 IN (m.to_message LIKE a.h_email WHERE a.h_email LIKE '%@%') OR 等
但我不断收到错误。
有什么想法吗？
非常感谢！
I am joining my address book onto my email table like this:
SELECT * FROM messages m
LEFT JOIN addr_book a ON
m.to_msg LIKE a.h_email
OR m.to_msg LIKE a.bill_email
OR m.to_msg LIKE a.b_email
OR m.to_msg LIKE a.w_email
OR m.to_msg LIKE a.other_email
OR m.from_msg LIKE a.h_email
OR m.from_msg LIKE a.bill_email
OR m.from_msg LIKE a.b_email
OR m.from_msg LIKE a.w_email
OR m.from_msg LIKE a.other_email
OR m.cc_msg LIKE a.h_email
OR m.cc_msg LIKE a.bill_email
OR m.cc_msg LIKE a.b_email
OR m.cc_msg LIKE a.w_email
OR m.cc_msg LIKE a.other_email
OR m.bcc_msg LIKE a.h_email
OR m.bcc_msg LIKE a.bill_email
OR m.bcc_msg LIKE a.b_email
OR m.bcc_msg LIKE a.w_email
OR m.bcc_msg LIKE a.other_email
The problem is it fetches everything, because some contacts don't have emails and join up with emails that don't have cc_msg='' or bcc_msg=''
Is there a way I can left join a table on a column where the column is like '@'??
I tried a couple things like IN (m.to_message LIKE a.h_email WHERE a.h_email LIKE '%@%') OR etc etc
But I keep getting errors.
Any ideas?
Thanks a ton!
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如果我理解你的问题，你需要使用 AND 而不是 WHERE：
我认为你可能意味着
=而不是 LIKE 对于第一个测试，这会给出这个：或者也许你只需要这个：
与 LIKE 不同，如果
a.h_email为空但m.to_message非空，则相等性测试将失败。If I understand your question, you need to use AND instead of WHERE:
I think you might mean
=instead of LIKE for the first test, which would give this:Or perhaps you just need this:
Unlike LIKE, an equality test will fail if
a.h_emailis empty butm.to_messageis non-empty.好的，这很有帮助。我不知道为什么，但我一直假设 = 在 mySQL 中区分大小写。我使用了以下内容，效果非常好。谢谢大家，我确信如果我接受过适当的培训，我一开始就不会犯这个错误，哈哈。
Ok so that helps out alot. I don't know why, but I have always assumed = is case sensitive in mySQL. I used the following and it works beautifully. Thanks all, I'm sure if I had proper training I wouldn't have made this mistake in the first place lol.