Question

I have first table like this:

ID    Email   

100  [e-mail]  
200  [e-mail]

I have second table like this(permissions shared):

   ID   Assigned ID  Role
   100    200        Normal user
   100    100        Super user
   200    200        Normal user 

ie. 100 is a super user and can access the sharing features of ID 200.

select t1.ID,t1.email,t2.role from table t1, table t2 where t1.ID=t2.ID;

When I combine both the top 2 tables, i get like this

ID     Email      Role

100    [e-mail]    Super  user 
100    [e-mail]    Normal user
200    [e-mail]    Normal user

I want to get output like this:

ID     Email      Role    
100    [e-mail]    Super  user 
200    [e-mail]    Normal user

ie. If any user has a type of super user rights, just take that entry and don’t need the type for normal user.

If the email is already present as super user and further the same email is assigned to someone, then the query should return only for super user.

I even tried using group by and union all:

  select t1.ID,t1.email,t2.role from table t1, table t2 
  where t1.ID=t2.ID group by t1.email having t2.role='Super user'
  and not exists (  select t1.ID,t1.email,t2.role from table t1, table t2 
  where t1.ID=t2.ID group by t1.email having t2.role='Super user')
  UNION ALL
  select t1.ID,t1.email,t2.role from table t1, table t2 
  where t1.ID=t2.ID group by t1.email having t2.role<>'Super user';

but seemed to give incorrect answer. Any thoughts?

Answer 1

“If any user has a type of super user rights, just take that entry and don’t need the type for normal user”:

select t1.ID,t1.email,t2.role 
from   table t1, table t2
where  t1.ID=t2.ID 
  and  t2.ID = t2.Assigned_ID

since you don’t need results where users are acting with another role.