SQL实现多个结果集合并（单表以及多表）-优快云博客

本文链接：https://blog.youkuaiyun.com/ASDFGQC/article/details/124312417

** 单表中多个结果集合并**

1.case when then end 实现
2.select 实现

下面举例如下
实现1

```sql
//1.
select 
count (case when user_type like 'T%' and create_time &gt;= #{dayStart} and create_time &lt; #{dayEnd} then 1 end) as teaSbNum,
count (case when user_type like 'S%' and create_time &gt;= #{dayStart} and create_time &lt; #{dayEnd} then 1 end) as stuSbNum,
count (case when user_type like 'P%' and create_time >= #{dayStart} and create_time &lt; #{dayEnd} then 1 end) as hzrySbNum
from epidemic_report_info

//2.
   select
        (select count(id)  from epidemic_report_info where user_type like 'T%' and create_time &gt;= #{dayStart} and create_time &lt; #{dayEnd}) teaSbNum,
        (select count(id)  from epidemic_report_info where user_type like 'S%' and create_time &gt;= #{dayStart} and create_time &lt; #{dayEnd}) stuSbNum,
        (select count(id)  from epidemic_report_info where user_type like 'P%' and create_time >= #{dayStart} and create_time &lt; #{dayEnd}) hzrySbNum

多表查询的结果集合并

1.union all 实现
2.select 实现
方式2同上不在举例，下面展示方式1

select teaTotal,stuTotal from (select count(id) as teaTotal from sys_user where user_identity  like 'T%'   union all  select count(id) as stuTotal from sys_user b where user_identity like 'S%') a