How to implement FIFO in sql

Question

I working on FIFO implementation in sql. I have Batch number concept in my application. If suppose I am selling on inventory then my application should tell me that which in

Answer 1

This should work for you:
Working sample on Fiddle

CREATE FUNCTION [dbo].[GetBatchAmounts]
(
    @requestedAmount int

)
RETURNS 
@tBatchResults TABLE 
(   
    Batch nvarchar(50),
    Amount int
)
AS
BEGIN
    /*This is just a mock of ersults of your query*/
    DECLARE @RS_GIN_Master TABLE( 

     Qty int,
     batch_no NVARCHAR(max),
     accept_date DATETIME
    )

    insert into @RS_GIN_Master(Qty,batch_no,accept_date)
    SELECT 10,'BT002', CAST(CAST(2014 AS varchar) + '-' + CAST(8 AS varchar) + '-' + CAST(4 AS varchar) AS DATETIME)

    insert into @RS_GIN_Master(Qty,batch_no,accept_date)
    SELECT 10,'BT003', CAST(CAST(2014 AS varchar) + '-' + CAST(8 AS varchar) + '-' + CAST(5 AS varchar) AS DATETIME)

    insert into @RS_GIN_Master(Qty,batch_no,accept_date)
    SELECT 10,'BT001', CAST(CAST(2014 AS varchar) + '-' + CAST(8 AS varchar) + '-' + CAST(6 AS varchar) AS DATETIME)
    /*---------------------------*/

     DECLARE @Qty int
     DECLARE @batch_no NVARCHAR(max)
     DECLARE @accept_date DATETIME


    DECLARE myCursor CURSOR FOR

    SELECT Qty, batch_no, accept_date FROM @RS_GIN_Master ORDER BY accept_date ASC

    OPEN myCursor

    FETCH NEXT FROM myCursor INTO  @Qty, @batch_no,@accept_date

    WHILE (@@FETCH_STATUS = 0 AND @requestedAmount > 0 ) 
    BEGIN

        Declare @actualQty int
        IF @requestedAmount > @Qty
            SET @actualQty = @Qty
        ELSE    
            SET @actualQty = @requestedAmount


        INSERT INTO @tBatchResults (batch, Amount)
        SELECT @batch_no, @actualQty

        set @requestedAmount  = @requestedAmount - @actualQty

        FETCH NEXT FROM myCursor INTO @Qty, @batch_no,@accept_date

    END /*WHILE*/

    CLOSE myCursor
    DEALLOCATE myCursor

    RETURN
END

Just make sure to replace the marked part of the function with your query...