Sql 如何检查一个表在另一个表中是否有匹配的记录？

我有以下表格：

表1:

AccessMenu

userid  item

1        a 

2        b    

2        c

idAdmin   itemCol

2          v

2          m

2          d

及

表2:ActionRights

userid  item

1        a 

2        b    

2        c

idAdmin   itemCol

2          v

2          m

2          d

所需结果：

  userid      yes/no

   1           no

   2           yes

当我在

ActionRight

中将

userid

匹配到

idadmin

时，它应该返回

Yes

否则

No

我尝试了以下查询：

select AccessMenu.userid,
case when ActionRights.IdAdmin=AccessMenu.userid then 'Yes' else 'No' end as 'GRP'
from AccessMenu left join ActionRights
on ActionRights.IdAdmin =AccessMenu.userid

但通过这个查询，我得到的重复结果如下：

 userid      yes/no

   1           no

   2           yes

   2           yes

   2           yes

   2           yes

   2           yes

---

请帮助我。

请使用子查询进行检查：

SELECT userid, 
       CASE 
         WHEN idadmin IS NULL THEN 'No' 
         ELSE 'Yes' 
       END AS 'Grp' 
FROM   (SELECT accessmenu.userid    AS UserId, 
               actionrights.idadmin AS IdAdmin 
        FROM   accessmenu 
               LEFT JOIN actionrights 
                      ON actionrights.idadmin = accessmenu.userid)z 

select distinct
    userid, 
    case when (SELECT COUNT(*) from ActionRights b where b.idAdmin=a.userid)>0 then 'Yes' else 'No' end [Yes/No]
from AccessMenu a

---

请使用子查询进行检查：

select distinct
    userid, 
    case when (SELECT COUNT(*) from ActionRights b where b.idAdmin=a.userid)>0 then 'Yes' else 'No' end [Yes/No]
from AccessMenu a

试试这个

SELECT distinct  UserId, CASE WHEN  IsAdmin  IS  NULL  THEN  'No'  ELSE  'Yes' END AS 'Grp'
FROM (  
      select AccessMenu.userid as UserId ,ActionRights.IsAdmin as IsAdmin
      from AccessMenu left join ActionRights
      on ActionRights.IsAdmin =AccessMenu.userid
     )a

看一看

试试这个

SELECT distinct  UserId, CASE WHEN  IsAdmin  IS  NULL  THEN  'No'  ELSE  'Yes' END AS 'Grp'
FROM (  
      select AccessMenu.userid as UserId ,ActionRights.IsAdmin as IsAdmin
      from AccessMenu left join ActionRights
      on ActionRights.IsAdmin =AccessMenu.userid
     )a

看一看

很简单。不需要内部查询或子查询。坐火车就行了 明显的

很简单。不需要内部查询或子查询。坐火车就行了 明显的