I'm trying to join two tables, but inputs are not the same.
我正在尝试加入两个表,但输入不一样。
On table Category category_id is an integer.
在表类别category_id是一个整数。
But on table url_alias category is a string like category_id=15.
但是在表url_alias类别是一个类似category_id = 15的字符串。
I've tried:
SELECT * FROM category c
LEFT JOIN url_alias ua ON ( ua.category = 'category_id=c.category_id')
No luck. How can I reach that table?
没运气。我怎样才能到达那张桌子?
1 个解决方案
#1
You have placed c.catagory_id inside the quotes ('), thus making it part of the string literal. Instead, you should concat its value to category_id= literal:
您已将c.catagory_id放在引号(')中,从而使其成为字符串文字的一部分。相反,您应该将其值连接到category_id = literal:
SELECT *
FROM category c
LEFT JOIN url_alias ua ON ua.category = CONCAT('category_id=', c.category_id)
#1
You have placed c.catagory_id inside the quotes ('), thus making it part of the string literal. Instead, you should concat its value to category_id= literal:
您已将c.catagory_id放在引号(')中,从而使其成为字符串文字的一部分。相反,您应该将其值连接到category_id = literal:
SELECT *
FROM category c
LEFT JOIN url_alias ua ON ua.category = CONCAT('category_id=', c.category_id)