创建索引

EXPLAIN SELECT a.id FROM ims_kdpartner_areaagentordera LEFT JOINims_kdpartner_memberb ON a.openid = b.openid WHERE a.uniacid = 693 ORDER BY a.id DESC LIMIT 0,20

EXPLAIN 结果中显示 type = ALL，说明 MySQL 没有使用索引，而是全表扫描，导致查询变慢。

重新创建索引