需要每隔一段时间选取最老的商户更新时间戳:
update DP_Shop set DP_Shop.LastDate = now() where DP_Shop.ShopId in (select ShopId from DP_Shop order by LastDate limit 5);
ERROR 1235 (42000): This version of MySQL doesn‘t yet support ‘LIMIT & IN/ALL/ANY/SOME subquery‘
多加一层:
update DP_Shop set DP_Shop.LastDate = now() where DP_Shop.ShopId in (select t.ShopId from (select ShopId from DP_Shop order by LastDate limit 5) as t);
可以work,但不高效，考虑下怎么优化。
最后是用临时表:
start transaction;
create temporary table tmp1986 (select ShopId from DP_Shop order by LastDate limit 1000);
update DP_Shop inner join tmp1986 on DP_Shop.ShopId = tmp1986.ShopId set LastDate = now();
DROP TABLE tmp1986;
commit;