Best way to join this into a temp table and inner join - sql

Question

Just wondering the best way to put this into a temp table and then join it.
IF EXISTS(SELECT LocId
FROM dbo.Locations WITH (NOLOCK)
WHERE SourceSystem = #SourceSystem
AND LocId IN (SELECT ListVal
FROM etopsuser.fnParseListToTable(#LocIdList, ';')) AND IsHot = 1)
BEGIN
Specifically trying to do it on this line of code
(SELECT ListVal
FROM etopsuser.fnParseListToTable(#LocIdList, ';')) AND IsHot = 1)
The NOLOCK is unrelated

Answer 1

You would create a temporary table just like any other table from a select:
SELECT ListVal
INTO #templist
FROM etopsuser.fnParseListToTable(#LocIdList, ';');
Then you would use it as:
SELECT l.LocId
FROM dbo.Locations l JOIN
#templist tl
ON l.LocId = tl.Listval
WHERE l.SourceSystem = #SourceSystem AND l.IsHot = 1

Answer 2

The best way to pass a list into a procedure is to use a Table Valued Parameter
CREATE TYPE dbo.List AS TABLE (ListVal varchar(255));
IF EXISTS(SELECT 1
FROM dbo.Locations l
WHERE l.SourceSystem = #SourceSystem
AND l.LocId IN (
SELECT ll.ListVal
FROM #LocIdList ll
) AND IsHot = 1)
Notes: Always use table references on every column, especially if subqueries are involved. Never use NOLOCK unless you are prepared for incorrect results. EXISTS ignores its SELECT, so SELECT 1 or SELECT NULL is standard.
Then you can pass in the table variable either from client code depending on language, or in T-SQL like this
DECLARE #list dbo.List;
INSERT #list (ListVal)
VALUES ('SomeValue');
EXEC YourProc #LocIdList = #list;