mysql 1kw数据 快速查询

Question

gift_id 有100多种

gift_id,user_id 建立了索引

只需要找拥有某一gift_id的用户的查询如下，而且速度非常快
select * from user_gift where gift_id = 1004302 group by user_id

怎么快速找到 同时拥有 gift_id 为1004302和1004004的用户user_id呢 ？

Answer 1

select t.user_id from table t INNER JOIN ( select id from table where gift_id in(1004302, 1004004)) AS x USING(id) group by t.user_id having count(1) > 1;

或者

select user_id from table where gift_id in(1004302, 1004004) group by user_id having count(1) > 1

因为没有测试环境，上面两个 SQL 都可以尝试一下看看。
如果有 gift_id,user_id 联合索引的话，下面一个 SQL 应该也还好吧。

Answer 2

查 gift_id 为1004302的用户存list1 查 gift_id 为1004004的用户存list2 两个list取交集

Answer 3

select t.user_id, count(1) as c from table as t
where t.gift_id in(1004302, 1004004)
group by t.user_id
having count(1)>1

效率问题, 没数据, 也测试不了

如果, (user_id, gift_id) 是有可能重复的, 那在计算同时拥有之前还得将 (user_id, gift_id) 去重.

select t.user_id, count(1) as c from (
select user_id, gift_id from table group by user_id, gift_id
) as t
where t.gift_id in(1004302, 1004004)
group by t.user_id
having count(1)>1