数据库表结构的情况如下：CREATETABLEds_settle_user(idint(11)NOTNULLAUTO_INCREMENT,user_idint(11)NOTNULLCOMMENT'userid',pidint(11)NOTNULLCOMMENT'referrerid，0为referrer为人，非0为上级推荐人',user_namevarchar(40)NOTNULL,PRIMARYKEY(id))ENGINE=InnoDBDEFAULTCHARSET=utf8;CREATETABLEds_user(idint(11)NOTNULLAUTO_INCREMENTCOMMENT'userid',user_namevarchar(40)NOTNULLCOMMENT'username',PRIMARYKEY(id))ENGINE=InnoDBDEFAULTCHARSET=utf8;需求：当pid值为0时，推荐人为自己，需要执行查询条件ds_settle_user表user_id等于ds_user表id链表查询，当pid不等于0时，查询ds_settle_user表pid等于ds_user表id数据示例：sql语句核心代码：SELECTb.*,a.user_nameASrefereeFROMds_userASaJOINds_settle_userASbON(CASEb.pidWHEN0THENa.id=b.user_idELSEa.id=b.pidEND)效果图如下：更多技术资料请关注：gzitcast
