How can I store into a temporary table multiple times in a while loop?

Question

I'm doing an inner join that appends a new column to my table every time it

For example, I'm trying to do this:

WHILE @Counter <= @MaxCount
BEGIN
    SELECT @ParameterDefinitionID = ParameterDefinitionID FROM #CachedParameterDefinitionIDs WHERE RowNumber = @Counter
    SELECT * INTO #ContactsWithPatientID FROM #ContactsWithPatientID INNER JOIN (SELECT Parameter2.ContactID AS 'Parameter2ContactID', Parameter2.Value AS FirstName FROM #CachedParameterValues Parameter2 WHERE ParameterDefinitionID = @ParameterDefinitionID) FirstNameTable ON #ContactsWithPatientID.ContactID = FirstNameTable.Parameter2ContactID
    SET @Counter = @Counter + 1
END

It doesn't work on the first iteration because:

There is already an object named '#ContactsWithPatientID' in the database.

How can I make it work? Is there some alternative way to do this? I am doing it this way because I need to append a certain number of rows as columns in my query.

Answer 1

Create the table first

CREATE TABLE #ContactsWithPatientID (...)
WHILE @Counter <= @MaxCount
BEGIN
    SELECT @ParameterDefinitionID = ParameterDefinitionID 
    FROM #CachedParameterDefinitionIDs
    WHERE RowNumber = @Counter

    INSERT #ContactsWithPatientID
    SELECT *
    FROM #ContactsWithPatientID 
            INNER JOIN 
            (SELECT Parameter2.ContactID AS 'Parameter2ContactID', Parameter2.Value AS FirstName 
            FROM #CachedParameterValues Parameter2 
            WHERE ParameterDefinitionID = @ParameterDefinitionID) FirstNameTable ON #ContactsWithPatientID.ContactID = FirstNameTable.Parameter2ContactID

    SET @Counter = @Counter + 1
END

This can almost certainly be done in one go too as a recursive CTE probably