问题描述
试试这个查询:
SELECT uid
FROM subscribes
GROUP BY uid
HAVING COUNT(*) > 2
AND max( CASE "subscription_type" WHEN 'type1' THEN 1 ELSE 0 END ) = 0
解决方法
假设我有一个订阅表:
uid | subscription_type
------------------------
Alex | type1
Alex | type2
Alex | type3
Alex | type4
Ben | type2
Ben | type3
Ben | type4
并且只想选择订阅数量超过2个但从未订阅过类型1的用户
预期结果是仅选择“ Ben”。
我很容易找到使用2个以上订阅的用户:
SELECT uid
FROM subscribes
GROUP BY uid
HAVING COUNT(*) > 2
但是,如何检查组中是否不存在某些值?
谢谢您的帮助!