NULL Values not Being Returned - sql

Question

I have a situation where I am running a query again tables MEMBERS, MEMBERUDFS, and MEMERUDFSETUPS. Where MEMBER UDFs are User Defined Fields that are created by the system admin to store data about customers in customizable fields. The UDFSETUPS table defines the configurable fields and MEMBERUDFS stores the values of those fields if they exist.
The issue I am running into is when I pull data back, I am not getting the rows for entries that have a UDF with an ID of 17 (MEMBERUDFS.udfid = '17') that do not have an entry or are null. I tried Left Joins but it did not seem to help.
SELECT MEMBERS.scancode, MEMBERS.fname, MEMBERS.lname, MEMBERS.datejoin, MEMBERS.entrydate
, MEMBERS.relationship, MEMBERUDFS.udfvalue
FROM MEMBERS
LEFT OUTER JOINMEMBERUDFS
ON MEMBERS.memid = MEMBERUDFS.memid
INNER JOIN MEMBERUDFSETUPS
ON MEMBERUDFS.udfid = MEMBERUDFSETUPS.udfid
WHERE (MEMBERS.siteid = #rvSite)
AND (MEMBERS.status = 'A')
AND (MEMBERS.relationship = 'M')
AND (MEMBERUDFS.udfid = '17')
AND (MEMBERS.datejoin BETWEEN #rvStartDate AND #rvEndDate)
AND (MEMBERS.mtypeid NOT IN (5, 6, 7, 11, 14, 31))
OR (MEMBERS.siteid = #rvSite)
AND (MEMBERS.relationship = 'P')
AND (MEMBERUDFS.udfid = '17')
AND (MEMBERS.entrydate BETWEEN #rvStartDate AND #rvEndDate)

Answer 1

Move the limit on the JoinMemberUDFS to the join or your nulls get excluded.
Preferred method move filter to join criteria
SELECT MEMBERS.scancode, MEMBERS.fname, MEMBERS.lname, MEMBERS.datejoin, MEMBERS.entrydate
, MEMBERS.relationship, MEMBERUDFS.udfvalue
FROM MEMBERS
LEFT JOIN MEMBERUDFS
ON MEMBERS.memid = MEMBERUDFS.memid
AND MEMBERUDFS.udfid = '17'
LEFT JOIN MEMBERUDFSETUPS
ON MEMBERUDFS.udfid = MEMBERUDFSETUPS.udfid
WHERE (MEMBERS.siteid = #rvSite
AND MEMBERS.status = 'A'
AND MEMBERS.relationship = 'M'
AND MEMBERS.datejoin BETWEEN #rvStartDate AND #rvEndDate
AND MEMBERS.mtypeid NOT IN (5, 6, 7, 11, 14, 31))
OR (MEMBERS.siteid = #rvSite
AND MEMBERS.relationship = 'P'
AND MEMBERS.entrydate BETWEEN #rvStartDate AND #rvEndDate)
Not preferred handle when it's null and ensure it returns true for the evaluation
SELECT MEMBERS.scancode, MEMBERS.fname, MEMBERS.lname, MEMBERS.datejoin, MEMBERS.entrydate
, MEMBERS.relationship, MEMBERUDFS.udfvalue
FROM MEMBERS
LEFT OUTER JOINMEMBERUDFS
ON MEMBERS.memid = MEMBERUDFS.memid
INNER JOIN MEMBERUDFSETUPS
ON MEMBERUDFS.udfid = MEMBERUDFSETUPS.udfid
WHERE (MEMBERS.siteid = #rvSite
AND MEMBERS.status = 'A'
AND MEMBERS.relationship = 'M'
AND MEMBERS.datejoin BETWEEN #rvStartDate AND #rvEndDate
AND MEMBERS.mtypeid NOT IN (5, 6, 7, 11, 14, 31)
AND (MEMBERUDFS.udfid = '17' or MEMBERUDFS.udfid is null)
OR (MEMBERS.siteid = #rvSite
AND MEMBERS.relationship = 'P'
AND MEMBERS.entrydate BETWEEN #rvStartDate AND #rvEndDate)
AND (MEMBERUDFS.udfid = '17' or MEMBERUDFS.udfid is null)