SQL Select only rows where exact multiple relationships exist

Question

This is closely related to this question, but adds another requirement.

Given a parent table \'parent\'

╔════════════╦════════╗
║ PARENT_ID  ║ NAME           


        

Answer 1

This alternative has the benefit of a constant statement structure and only one parameter, independent of the amount of relations you are looking for:

SELECT parent_id FROM rel 
GROUP BY parent_id 
HAVING GROUP_CONCAT(prop_id ORDER BY prop_id ASC SEPARATOR ",") = '1,5';

Disadvantages:

• You need to prepare an ordered, comma separated String of prop_ids upfront.
• This works on MySQL, but not all database servers.

Answer 2

You can do this with a group by.

SELECT PARENT_ID FROM link_tbl WHERE PROP_ID IN (5,1) GROUP BY PARENT_ID HAVING COUNT(*) = 2

Answer 3

If you want to select all parents with at least a 5 and a 1, you can use:

SELECT PARENT_ID
FROM rel
GROUP BY PARENT_ID
HAVING SUM(PROP_ID = 1)
       AND SUM(PROP_ID = 5)
       AND SUM(PROP_ID NOT IN (5,1)) = 0

If you need exactly one 5 and one 1, see this answer

Answer 4

With two nested subqueries, like this..

 Select pa.Id
 From parents pa
 Where not exists -- This ensures that all specifies properties exist
    (Select * From property y
     Where propertyId In (1,5)
         And Not Exists
             (Select * From parentProperty
              Where parentId = pa.parentId 
                  And propertyId = y.propertyId ))
   And not exists -- This ensures that only specified list of properties exist
    (Select * From parentProperty
     Where parentId = pa.parentId 
        And propertyId Not In (1,5) )

The first one reads "Show me all the parents where there is not a property in the specified list of properties that is not in the parent properties table for the specified parent...."

The second subquery reads: "also make sure that there does not exist a record in the parentProperties table for that parent for any property that is not in the specified list."

Answer 5

If MySql supported minus, the query could look like this:

select parent_id
from rel
where prop_id in (5,1)
group by parent_id
having count(distinct prop_id)=2 and count(prop_id)=2
minus
select parent_id
from rel
where prop_id not in (5,1);

The not in will remove those relationships that exceed (5,1), e.g. (5,1,3).

I know you're using MySql and my answer hence is wrong. Just take it as another idea.

Answer 6

SELECT PARENT_ID
FROM rel
GROUP BY PARENT_ID
HAVING SUM(PROP_ID NOT IN (5,1)) = 0
AND SUM(PROP_ID = 1) = 1 
AND SUM(PROP_ID = 5) = 1