Mysql 在两列上连接三个表
我用这个来连接3个表Mysql 在两列上连接三个表,mysql,Mysql,我用这个来连接3个表 FROM TABLE_A LEFT JOIN TABLE_B ON A.Name = B.Name LEFT JOIN TABLE_C ON A.Name = C.Name 每当我尝试像 FROM TABLE_A LEFT JOIN TABLE_B ON A.Name = B.Name, A.Number = B.Number LEFT JOIN TABLE_C ON A.Name = C.Name, A.Number = C.Number 它告诉我这个
FROM TABLE_A LEFT JOIN TABLE_B ON A.Name = B.Name
LEFT JOIN TABLE_C ON A.Name = C.Name
每当我尝试像
FROM TABLE_A LEFT JOIN TABLE_B ON A.Name = B.Name, A.Number = B.Number
LEFT JOIN TABLE_C ON A.Name = C.Name, A.Number = C.Number
它告诉我这个操作只能使用一列。不过,我需要在两个不同的列上进行连接,所以我不能在第一个示例中保留它。使用AND对我也没有帮助。尝试用运算符替换双重测试之间的逗号 例如:
FROM TABLE_A LEFT JOIN TABLE_B ON A.Name = B.Name AND A.Number = B.Number
LEFT JOIN TABLE_C ON A.Name = C.Name AND A.Number = C.Number