SQL - Conditional Selection - sql

Question

I am trying to build an Oracle SQL query where I select users that contain at least one License = '+' while all Default Orgs = '-'. In other words, select users with licenses that have no default organizations. In the example below I would expect only Annete to show in the result.
Table_Users: User, License
Table_Organizations: Default_Org, Org_Name
Query below returns no results:
select User
from Table_Users, Table_Organizations
where Table_Users.User = Table_Organizations.UsrX
and (Default_Org = '+' and Default_Org = '-')*

Answer 1

select User
from Table_Users, Table_Organizations
where Table_Users.User = Table_Organizations.UsrX
and License = '+' and Default_Org = '-'

Answer 2

SELECT
u.User
FROM
Table_Users u
INNER JOIN Table_Organizations o
ON u.User = o.Usrx
GROUP BY
u.User
HAVING
COUNT(CASE WHEN License = '+' THEN 1 END) > 0
AND COUNT(CASE WHEN Default_Org = '+' THEN 1 END) = 0
First I would suggest using Explicit not Implicit join, it is a pet peeve of mine and I think a number of others on this site as Explicit join has been part of the ANSI SQL standard for a lot of years now.
As far as what technique you actually want would be called conditional aggregation. By counting only the values you are looking for you can then use them in a HAVING clause to exclude the record(s) you don't want.
Note COUNT(CASE WHEN... THEN END) will work because only the value you want will have a value to be counted and anything not meeting that condition will be NULL and therefore not counted.
Because I don't know which table has License on it you could also potentially use exists as follows:
SELECT
u.User
FROM
Table_Users u
WHERE
u.License = '+'
AND NOT EXISTS(SELECT 1 FROM Table_Organizations o WHERE u.User = o.Usrx AND Default_Org = '+')

Answer 3

Knowing + comes before - we can use a min aggregate. This assumes license and default org could only have '+' or '-' values.
With cte ("user", license, default_org, org_name) as (
SELECT 'Jeff','+','+', 'Org 1' FROM DUAL UNION ALL
SELECT 'Jeff','-','-', 'Org 2' FROM DUAL UNION ALL
SELECT 'Jeff','-','-', 'Org 3' FROM DUAL UNION ALL
SELECT 'Annete','+','-', 'Org 4' FROM DUAL UNION ALL
SELECT 'Annete','-','-', 'Org 5' FROM DUAL)
SELECT "user", min(license), Min(default_org)
FROM CTE A
GROUP BY "user"
HAVING min(license) = '+'
AND min(Default_org) = '-';
If license and default_org both have indexes with user; this would be pretty fast.