在SQL中合并两个查询

Question

Basically I need to combine the result of these two queries where the PSROLEUSER is equal in both tables. How would I do this?

select PSROLEUSER from sysadm.PSROLEUSER where ROLENAME = 'NCC_Manag';
select PSROLEUSER from sysadm.PSROLEUSER where ROLENAME = 'HRM-Content Amin';

Answer 1

The query below assumes that ROLENAME is unique for every PSROLEUSER .

SELECT  PSROLEUSER 
FROM    sysadm.PSROLEUSER 
WHERE   ROLENAME IN ('NCC_Manag', 'HRM-Content Amin')
GROUP   BY PSROLEUSER
HAVING  COUNT(*) = 2

• SQL of Relational Division

Answer 2

Here is an approach that puts all the logic in the having clause:

select PSROLEUSER
from sysadm.PSROLEUSER 
group by PSROLEUSER
having sum(case when ROLENAME = 'NCC_Manag' then 1 else 0 end) > 0 and
       sum(case when ROLENAME = 'HRM-Content Amin' then 1 else 0 end) > 0;

I like this approach because it is quite general. For instance, if you wanted all 'NCC_Manag' that are not 'HRM_Content Amin' , you would do:

select PSROLEUSER
from sysadm.PSROLEUSER 
group by PSROLEUSER
having sum(case when ROLENAME = 'NCC_Manag' then 1 else 0 end) > 0 and
       sum(case when ROLENAME = 'HRM-Content Amin' then 1 else 0 end) = 0;

Answer 3

Another way:

select X.PSROLEUSER from
(select PSROLEUSER from sysadm.PSROLEUSER where ROLENAME = 'NCC_Manag') X inner join 
(select PSROLEUSER from sysadm.PSROLEUSER where ROLENAME = 'HRM-Content Amin') Y
on X.PSROLEUSER = Y.PSROLEUSER

Answer 4

select PSROLEUSER from sysadm.PSROLEUSER where ROLENAME in('NCC_Manag','HRM-Content Amin')

试试这个代码

Answer 5

select PSROLEUSER from sysadm.PSROLEUSER where ROLENAME = 'NCC_Manag'
UNION
select PSROLEUSER from sysadm.PSROLEUSER where ROLENAME = 'HRM-Content Amin'

Assuming they return the same schema, just union them.

Answer 6

Also you can use another version with EXISTS operator.

SELECT t1.PSROLEUSER
FROM sysadm.PSROLEUSER t1
WHERE t1.ROLENAME = 'NCC_Manag'
  AND EXISTS (
              SELECT 1
              FROM sysadm.PSROLEUSER t2
              WHERE t2.ROLENAME = 'HRM-Content Amin'
                AND t1.PSROLEUSER = t2.PSROLEUSER
              )

See demo on SQLFiddle

Answer 7

select distinct psroleuser from psroleuser where rolename = 'NCC_Manag'
and psroleuser in 
(select psroleuser from psroleuser where rolename = 'HRM-Content Amin')