SQL 优化慢的update语句

原语句

 UPDATE tbl_mix_traceSET mix_plan_id = ( SELECT p.id FROM tbl_mix_plan p WHERE p.lot_id_out= lot_id_in ),pro_date_in = (SELECT p.pro_date_out FROM tbl_mix_plan p WHERE p.lot_id_out = lot_id_in),shift_id_in = (SELECT p.shift_id_out FROM tbl_mix_plan p WHERE p.lot_id_out = lot_id_in),equip_id_in = (SELECT p.equip_id_out FROM tbl_mix_plan p WHERE p.lot_id_out = lot_id_in)where   <![CDATA[( lot_id_in <> '' and lot_id_in is not NULL)]]>and pro_date_out = #{proDateOut}and shift_id_out = #{shiftIdOut}

原因

• 使用了过多的子查询，查询的还是同一个表，效率低
• 使用join 可以避免这个问题（不同的数据库写法可能不同）

更改后的语句

UPDATE t
SET t.mix_plan_id = p.id,t.pro_date_in = p.pro_date_out,t.shift_id_in = p.shift_id_out,t.equip_id_in = p.equip_id_out
FROM tbl_mix_trace t
JOIN tbl_mix_plan p ON p.lot_id_out = t.lot_id_in
WHERE t.lot_id_in <> '' AND t.lot_id_in IS NOT NULLAND t.pro_date_out = '2024-08-14'AND t.shift_id_out = 1;