select order_id FROM yzj_store_order t WHERE (t.user_id,t.order_status) IN ( SELECT user_id,order_status FROM yzj_store_order where order_status=0 AND DATE_FORMAT( create_date, '%Y-%m-%d' ) = DATE_FORMAT( CURDATE( ) - 0, '%Y-%m-%d' ) GROUP BY user_id…
1.存在两条完全相同的纪录 这是最简单的一种情况,用关键字distinct就可以去掉 select distinct * from table(表名) where (条件) 2.存在部分字段相同的纪录(有主键id即唯一键) 如果是这种情况的话用distinct是过滤不了的,这就要用到主键id的唯一性特点及group by分组 select * from table where id in (select min(id) from table group by [去除重复的字段名列表,....])…
Farmer John's N cows (1 ≤ N ≤ 100,000) share many similarities. In fact, FJ has been able to narrow down the list of features shared by his cows to a list of only K different features (1 ≤ K ≤ 30). For example, cows exhibiting feature #1 might have s…
更新UPDATE mytable SET myfield = CASE id WHEN 1 THEN 'value' WHEN 2 THEN 'value' WHEN 3 THEN 'value' END WHERE id IN (1,2,3) 查重 select t.* from vinstatic t inner JOIN (select vin, count(0) num from vinstatic group by vin) t1 on t.VIN=t1.vin where t1.nu…
