使用复合主键的 SQL 连接
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SQL join with composite primary key
提问by Anubh
I have to join two tables. But in one table primary key is not there,composite primary key is there,means three columns put together uniquely define a row of that table. I have those three columns in the other table too.rest nothing is common. Is there any way to join these two tables.please explain with the help of example
我必须加入两个表。但是在一个表中没有主键，有复合主键，意味着三列放在一起唯一地定义了该表的一行。我在另一个表中也有这三列。其余的没有什么共同之处。有什么办法可以连接这两个表，请举例说明
回答by Eterm
You can use AND in the expression for the ON criteria and demand the fields are all equal there.
您可以在 ON 条件的表达式中使用 AND 并要求所有字段在那里都相等。
SELECT *
FROM Table1
INNER JOIN Table2
ON Table1.Key1 = Table2.Key1 AND Table1.Key2 = Table2.Key2 AND Table1.Key3 = Table2.Key3
