SQL: Select IDs which are not mapped to values in another column - sql

Question

I have table with two columns like this:
ROLE_ID RESTRICTION_ID
--------- ---------------
2 null
2 15
2 null
13 12
13 null
13 13
555 null
555 null
555 null
91 10
91 12
91 null
I need to get:
ROLE_ID RESTRICTION_ID
--------- ---------------
555 null
555 null
555 null
Meaning , that i need all ROLE_ID's which are not connected to any RESTRICTION_ID.
If there is some number in the RESTRICTION_ID column for some ROLE_ID is want the ROLE_ID excluded from the select statement results.

Answer 1

SELECT t1.*
FROM
table t1
LEFT JOIN table t2
ON t1.ROLE_ID = t2.ROLE_ID
AND t2.RESTRICTION_ID IS NOT NULL
WHERE
t2.ROLE_ID IS NULL
Just because everyone else is showing the WHERE IN (SELECT ... answer here is a way to do it via a self join....
And just to show one way it can be done using EXISTS...
SELECT t1.*
FROM
table t1
WHERE
NOT EXISTS (SELECT *
FROM
table t2
WHERE
t1.ROLE_ID = t2.ROLE_ID
AND t2.RESTRICTION_ID IS NOT NULL)

Answer 2

Select the rows where resctriction_id is null
select * from my_table
where resctiction_id is null
and role_id not in (select role_id from my_table where resctiction_id is not null) ;

Answer 3

The following should get you started:
SELECT
role_id
, restriction_id
FROM Data
WHERE role_id NOT IN
(SELECT
role_id
FROM Data
GROUP BY role_id
HAVING COUNT(restriction_id) > 0
);
Please comment if and as this requires adjustment / further detail.

Answer 4

Select role_id, restriction_id
From Table
Where role_id in (Select ROLE_ID
From Table
Group by ROLE_ID
Having COUNT(RESTRICTION_ID)=0)
Better maybe...

Answer 5

SELECT ROLE_ID, RESTRICTION_ID
FROM <Your Table>
WHERE RESTRICTION_ID IS NULL
AND ROLE_ID NOT IN
(SELECT ROLE_ID FROM <Your Table> WHERE RESTRICTION_ID IS NOT NULL) sub

Answer 6

and becuase you have tagged SQL here is a Window function with common table expression that does the job nicely as well.
WITH cte AS (
SELECT
*
,COUNT(RESTRICTION_ID) OVER (PARTITION BY ROLE_ID) as CountOfRestrictionsIds
FROM
TableName
)
SELECT *
FROM
cte
WHERE
CountOfRestrictionsIds = 0

Answer 7

SELECT ROLE_ID, RESTRICTION_ID
FROM Table
WHERE
ROLE_ID NOT IN (SELECT ROLE_ID FROM Table WHERE RESTRICTION_ID IS NOT NULL)

Answer 8

Count them all
with t as (
-- sample data
select 2 as ROLE_ID ,null as RESTRICTION_ID from dual union all
select 2 ,15 from dual union all
select 2 ,null from dual union all
select 13 ,12 from dual union all
select 13 ,null from dual union all
select 13 ,13 from dual union all
select 555 ,null from dual union all
select 555 ,null from dual union all
select 555 ,null from dual union all
select 91 ,10 from dual union all
select 91 ,12 from dual union all
select 91 ,null from dual
)
select ROLE_ID,RESTRICTION_ID
from (
select t.*
,count(RESTRICTION_ID) over(partition by ROLE_ID) as cnt
from t
) x
where cnt=0;