Mysql查询问题

Question

我有两列，一列是member_id，另一列是connection_member_id。我必须检查member和connection_member是否已经插入到数据库中，然后不要插入它。

尝试获取类似的东西

SELECT * FROM `mlm_connections` mc 
LEFT JOIN temp_connections_members tcm 
ON tcm.member_id != mc.member_id 
AND tcm.connection_member_id != mc.connection_member_id;

Answer 1

试试这个

SELECT * FROM `mlm_connections` mc 
WHERE mc.member_id  NOT Exists (SELECT member_id  FROM temp_connections_members) AND    
      mc.connection_member_id NOT Exists (SELECT connection_member_id  FROM temp_connections_members)