Translate Excel business logic to T-SQL

I need to ‘translate’ some business logic from Excel to T-SQL, I’m having a hard time with it.

It’s about figures from gates that count how many customers go IN and OUT of the stores.

All DATA you need is in the following table:

CREATE TABLE #ResultsTable 
(
    Datum DATETIME,
    window CHAR(10),
    countersOUT INT,
    countersIN INT,
    RESULT INT
)

INSERT INTO #ResultsTable 
VALUES ('20180104 08:30:00.000', '08:30', 0, 0, 0),
       ('20180104 09:00:00.000', '09:00', 2, 1, 1),
       ('20180104 09:30:00.000', '09:30', 1, 0, 2),
       ('20180104 10:00:00.000', '10:00', 25, 9, 18),
       ('20180104 10:30:00.000', '10:30', 45, 41, 22),
       ('20180104 11:00:00.000', '11:00', 38, 37, 23),
       ('20180104 11:30:00.000', '11:30', 50, 51, 22),
       ('20180104 12:00:00.000', '12:00', 21, 24, 19),
       ('20180104 12:30:00.000', '12:30', 12, 19, 12),
       ('20180104 13:00:00.000', '13:00', 25, 18, 19),
       ('20180104 13:30:00.000', '13:30', 35, 27, 27),
       ('20180104 14:00:00.000', '14:00', 81, 9, 52),
       ('20180104 14:30:00.000', '14:30', 113, 18, 70),
       ('20180104 15:00:00.000', '15:00', 116, 34, 71),
       ('20180104 15:30:00.000', '15:30', 123, 36, 54),
       ('20180104 16:00:00.000', '16:00', 127, 35, 50),
       ('20180104 16:30:00.000', '16:30', 103, 19, 47),
       ('20180104 17:00:00.000', '17:00', 79, 31, 27),
       ('20180104 17:30:00.000', '17:30', 50, 16, 26),
       ('20180104 18:00:00.000', '18:00', 28, 11, 17),
       ('20180104 18:30:00.000', '18:30', 16, 15, 2),
       ('20180104 19:00:00.000', '19:00', 0, 2, 0),
       ('20180104 19:30:00.000', '19:30', 0, 0, 0),
       ('20180104 20:00:00.000', '20:00', 0, 0, 0),
       ('20180104 20:30:00.000', '20:30', 0, 0, 0),
       ('20180104 21:00:00.000', '21:00', 0, 0, 0),
       ('20180104 21:30:00.000', '21:30', 0, 0, 0),
       ('20180104 22:00:00.000', '22:00', 0, 0, 0)

select * from #ResultsTable

‘RESULT’ is the column that should be calculated, based on ‘countersOUT and ‘countersIN’.

‘countersOUT and ‘countersIN’ is the INPUT data you need for the calculation.

The business user made a help column in Excel to make the calculation (column AA) . . . . . . .From business point of view: this is the number of customers at the end of each half hour present in the shop.

Then, the actual calculation below: (screenshot also from Excel)

Note: the calculation makes use of the help column (col. AA)

Now my task is to make over this calculation in T-SQL.

The business user its only input data is ‘countersIN’ and ‘countersOUT’, in other words it should be achievable in T-SQL. Only, I don’t manage, that’s why I came to ask my question.

Lastly, I can advise to have a look at the Excel file (mediafire link) http://www.mediafire.com/file/mtdvlgmmbj3f8dd/Example_20190725_SQLforum.xlsx/file

Thanks a lot in advance for any help

Answer

Here’s a solution using a Cursor. No good style but effective, since you move through the rows. The attribut [RESULT_by_Cursor] is the computed one in comparison to your target value.

Btw: Your SQL-example has an error, the in and out – columns are twisted.

CREATE TABLE #ResultsTable 
(
    Datum DATETIME,
    window CHAR(10),
    countersIN INT,--countersOUT INT,
    countersOUT INT,--countersIN INT,
    RESULT INT,
    RESULT_by_Cursor INT,
    countersIN_corrected INT
);


INSERT INTO #ResultsTable 
VALUES ('20180104 08:30:00.000', '08:30', 0, 0, 0, NULL, NULL),
       ('20180104 09:00:00.000', '09:00', 2, 1, 1, NULL, NULL),
       ('20180104 09:30:00.000', '09:30', 1, 0, 2, NULL, NULL),
       ('20180104 10:00:00.000', '10:00', 25, 9, 18, NULL, NULL),
       ('20180104 10:30:00.000', '10:30', 45, 41, 22, NULL, NULL),
       ('20180104 11:00:00.000', '11:00', 38, 37, 23, NULL, NULL),
       ('20180104 11:30:00.000', '11:30', 50, 51, 22, NULL, NULL),
       ('20180104 12:00:00.000', '12:00', 21, 24, 19, NULL, NULL),
       ('20180104 12:30:00.000', '12:30', 12, 19, 12, NULL, NULL),
       ('20180104 13:00:00.000', '13:00', 25, 18, 19, NULL, NULL),
       ('20180104 13:30:00.000', '13:30', 35, 27, 27, NULL, NULL),
       ('20180104 14:00:00.000', '14:00', 81, 9, 52, NULL, NULL),
       ('20180104 14:30:00.000', '14:30', 113, 18, 70, NULL, NULL),
       ('20180104 15:00:00.000', '15:00', 116, 34, 71, NULL, NULL),
       ('20180104 15:30:00.000', '15:30', 123, 36, 54, NULL, NULL),
       ('20180104 16:00:00.000', '16:00', 127, 35, 50, NULL, NULL),
       ('20180104 16:30:00.000', '16:30', 103, 19, 47, NULL, NULL),
       ('20180104 17:00:00.000', '17:00', 79, 31, 27, NULL, NULL),
       ('20180104 17:30:00.000', '17:30', 50, 16, 26, NULL, NULL),
       ('20180104 18:00:00.000', '18:00', 28, 11, 17, NULL, NULL),
       ('20180104 18:30:00.000', '18:30', 16, 15, 2, NULL, NULL),
       ('20180104 19:00:00.000', '19:00', 0, 2, 0, NULL, NULL),
       ('20180104 19:30:00.000', '19:30', 0, 0, 0, NULL, NULL),
       ('20180104 20:00:00.000', '20:00', 0, 0, 0, NULL, NULL),
       ('20180104 20:30:00.000', '20:30', 0, 0, 0, NULL, NULL),
       ('20180104 21:00:00.000', '21:00', 0, 0, 0, NULL, NULL),
       ('20180104 21:30:00.000', '21:30', 0, 0, 0, NULL, NULL),
       ('20180104 22:00:00.000', '22:00', 0, 0, 0, NULL, NULL)




-- PDO: Apply Cursor to run through datasets


DECLARE @Datum DATETIME,
    @window CHAR(10),
    @countersOUT INT,           -- U
    @countersIN INT,            -- V
    @countersOUT_next INT,          -- V + 1 row
    @countersOUT_nextnext INT,          -- V + 2 rows
    @countersIN_corrected INT,
    @RESULT_by_Cursor INT;         --AA

DECLARE C_Tag CURSOR FAST_FORWARD FOR 
    SELECT Datum,
           window,
           countersOUT,
           countersIN

    FROM #ResultsTable
    ORDER BY Datum ASC
    ;


-- PDO: Cursor open and first fetch
SET @countersIN_corrected=0;
SET @RESULT_by_Cursor=0;

OPEN C_Tag

    FETCH NEXT FROM C_Tag INTO @Datum,
                               @window,
                               @countersOUT,
                               @countersIN

                               ;

    WHILE @@FETCH_STATUS=0

        BEGIN

            -- PDO: Get upcoming data in case we need them
            SET @countersOUT_next = ISNULL((SELECT TOP 1 r.countersOUT
                FROM #ResultsTable r
                WHERE r.Datum > @Datum
                ORDER BY r.Datum
                ),0)
            ;


            SET @countersOUT_nextnext = ISNULL((SELECT TOP 1 r.countersOUT
                FROM #ResultsTable r
                WHERE r.Datum > (SELECT TOP 1 r2.Datum
                                FROM #ResultsTable r2
                                WHERE r2.Datum > @Datum
                                ORDER BY r2.Datum
                                )
                ORDER BY r.Datum
                ),0)
            ;

            -- PDO: Compute correction according to Formula
            SET @countersIN_corrected=IIF(@RESULT_by_Cursor + @countersIN - @countersOUT < 0 ,

                                            @countersOUT ,

                                            IIF(@RESULT_by_Cursor + @countersIN - @countersOUT > (@countersOUT_next + @countersOUT_nextnext)    ,

                                                @countersOUT_next + @countersOUT_nextnext + @countersOUT - @RESULT_by_Cursor ,

                                                @countersIN

                                            )

                                        );



            -- PDO: Compute Result by cursor

            SET @RESULT_by_Cursor=@RESULT_by_Cursor + @countersIN_corrected - @countersOUT;



            -- PDO: Update Table with computed result

            UPDATE #ResultsTable
            SET RESULT_by_Cursor=@RESULT_by_Cursor,
                countersIN_corrected=@countersIN_corrected
            WHERE Datum=@Datum
            ;



            FETCH NEXT FROM C_Tag INTO @Datum,
                                       @window,
                                       @countersOUT,
                                       @countersIN

                                       ;


        END -- @@Fetch_Status C_Tag

CLOSE C_Tag;
DEALLOCATE C_Tag;



-- PDO: Clean Up

select * from #ResultsTable;


DROP TABLE #ResultsTable;

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