mysql - 索引该查询

Question

部分查询:

    FROM
        pm_data AS pmdata
        LEFT JOIN messages as pm
            ON pmdata.msg_id = pm.msg_id
        LEFT JOIN users as usr
            ON (usr.uid = pm.reciever_id || usr.uid = pm.sender_id)
    WHERE

        (
            pmdata.sender_id = 541839243781
            AND
            pmdata.sender_isdeleted = 1
        )
        OR
        (
            pmdata.reciever_id = 541839243781
            AND
            pmdata.reciever_isDeleted = 1
        )

    ORDER BY pm.created_at DESC

目前我只添加了

• 索引1(msg_id)
• index2(sender_isDeleted)

Answer 1

仅对于此查询，有用的索引是:

• pmdata(sender_id)
• pmdata(reciever_id)
• 消息(msg_id)
• 用户(uid)

此查询不需要您提到的内容:

• 索引1(msg_id)
• index2(sender_isDeleted)