How we can take dynamic variable in custom query

How we take dynamic parameter in custom query while writing custom query?

FOR EXAMPLE
I want add dynamic parameter instead of 'shared_referrals.shared_ounit_id =21 ’

SELECT assessments.,shared_referrals.shared_ounit_id ’
FROM shared_referrals
LEFT JOIN assessments ON shared_referrals.ounit_id = assessments.ounit_id
WHERE assessments.created >= shared_referrals.start_date AND assessments.created <= shared_referrals.end_date
AND shared_referrals.shared_ounit_id =21
GROUP BY assessments.id
UNION
SELECT assessments.
,assessments.ounit_id from assessments
Where assessments.ounit_id = 21

Hello @Warrenlautz ,
Using parameters in a DIRECT QUERY is in preview (almost ready to be GA). This functionality will let you use parameters within the query and therefore dynamically change the value used in a query clause.
If you want to know more about this feature I would suggest you to reach out your QuickSight contact and they can share more details.
Br,
JoseB