How to improve the code of stored procedure with inner join to possible empty tvp

Question

I want to improve the code of the following stored procedure. I want to join it into single select statement. Can you purpose a better way?

CREATE PROCEDURE [dbo].[pr_FinDocument_Filter]
  @finDocIdForFilter [dbo].[GuidList] READONLY,
  @filteredSid nvarchar(64),
  @filteringOffsetInDay int
AS
BEGIN

    IF (@filteredSid is null or @filteringOffsetInDay is null)
        BEGIN
            RAISERROR(N'arguments must have a value', 15, 1);
        END

    IF EXISTS (SELECT 1 FROM @finDocIdForFilter)
        BEGIN
            SELECT fin_doc_extra.docId
            FROM
                [CpsOther].[dbo].[FinDocumentExtra] AS fin_doc_extra
                INNER JOIN @finDocIdForFilter       AS fin_doc_for_filter
                    ON fin_doc_extra.docId = fin_doc_for_filter.Id
                    AND fin_doc_extra.sid = @filteredSid
            WHERE
                DATEDIFF(DAY, CONVERT(DATE, fin_doc_extra.value, 105), CONVERT(DATE, GETDATE(), 126)) = @filteringOffsetInDay
        END
    ELSE
        BEGIN
            SELECT fin_doc_extra.docId
            FROM
                [CpsOther].[dbo].[FinDocumentExtra] AS fin_doc_extra
            WHERE
                fin_doc_extra.sid = @filteredSid
                AND DATEDIFF(DAY, CONVERT(DATE, fin_doc_extra.value, 105), CONVERT(DATE, GETDATE(), 126)) = @filteringOffsetInDay
        END

END

Answer 1

I think that merging 2 selects into one will not necessary improve your code. For comparison, here is an example how you can do that. We have 1 query but it is more complex and can be perceived as less readable.

The query below is based on your your second query. I modified it by adding an additional condition to WHERE statement. This extra condition will be satisfied if @finDocIdForFilter is empty or if @finDocIdForFilter contains matching rows.

SELECT fin_doc_extra.docId
FROM
    [CpsOther].[dbo].[FinDocumentExtra] AS fin_doc_extra
WHERE
    fin_doc_extra.sid = @filteredSid AND
    DATEDIFF(DAY, CONVERT(DATE, fin_doc_extra.value, 105), CONVERT(DATE, GETDATE(), 126)) = @filteringOffsetInDay 
    AND
    (
        NOT EXISTS(SELECT 1 FROM @finDocIdForFilter) 
        OR 
        EXISTS(
            SELECT 1 
            FROM @finDocIdForFilter AS fin_doc_for_filter
                ON fin_doc_extra.docId = fin_doc_for_filter.Ida.AssetCode)
    )

Answer 2

I think this might work for you.

SELECT  fin_doc_extra.docID
FROM    [CpsOther].[dbo].[FinDocumentExtra] AS fin_doc_extra
WHERE   DATEDIFF(DAY, CONVERT(DATE, fin_doc_extra.value, 105),
                 CONVERT(DATE, GETDATE(), 126)) = @filteringOffsetInDay
        AND fin_doc_extra.sid = @filteredSid
        AND ( ( fin_doc_extra.docId IN ( SELECT fin_doc_for_filter.Id
                                         FROM   @finDocIdForFilter ) )
              OR ( NOT EXISTS ( SELECT  1
                                FROM    @finDocIdForFilter )
                 )
            );

Answer 3

I have an idea about left outer join

SELECT TABLEA.Id
FROM
    TABLEA
    left join TVP
        on TVP.Id = TABLEA.Id
WHERE
    TABLEA.sid = @filteredSid
    AND DATEDIFF(DAY, CONVERT(DATE, TABLEA.value, 105), CONVERT(DATE, GETDATE(), 126)) = @filteringOffsetInDay
    AND
    (
        TVP.Id is not null
        OR
        NOT EXISTS (SELECT 1 FROM TVP)
    )