SQL Server RunningCOUNT Function

Updated 2023-11-14 14:32:04.087000

Description

Use the scalar function to show how many rows are included in an ordered resultant table or within a partition in the resultant table, without having to do a self-join. The count is calculated over all the values from the first value to the last value in the ordered group or partition. If the column values are presented to the functions out of order, an error message will be generated.

Syntax

SELECT [westclintech].[wct].[RunningCOUNT](
  <@Val, sql_variant,>
 ,<@RowNum, int,>
 ,<@Id, tinyint,>
 ,<@CountNulls, bit,>)

Arguments

@Val

the value passed into the function. @Val is an expression of type float or of a type that can be implicitly converted to float.

@RowNum

the number of the row within the group for which the sum is being calculated. If @RowNum for the current row in a set is less than or equal to the previous @RowNum and @RowNum is not equal to 1, an error message will be generated. @RowNum is an expression of type int or of a type that can be implicitly converted to int.

@Id

a unique identifier for the RunningCOUNT calculation. @Id allows you to specify multiple RunningCOUNT calculation s within a resultant table. @Id is an expression of type tinyint or of a type that can be implicitly converted to tinyint.

@CountNulls

Indicates whether NULL values are included in the count. Enter 'True' to count NULL or 'False' not to count NULL. @CountNulls is an expression of type bit or of a type that can be implicitly converted to bit.

Return Type

float

Remarks

If @Id is NULL then @Id = 0.

To calculate moving count, use the MovingCOUNT function.

@RowNum must be in ascending order.

There may be cases where the order in which the data are returned to the function and the order in which the results are returned are different, generally due to parallelism. You can use OPTION(MAXDOP 1) or OPTION(MAXDOP 1,FORCE ORDER) to help eliminate this problem.

Examples

In this example we will calculate the running count of items for a check book. We will create a temporary table, #c, populate it with some data and then run the SELECT.

--Create the temporary table
CREATE TABLE #c
(
    trn int,
    cust_ref varchar(5),
    date_trn datetime,
    payee varchar(20),
    amt_trn money,
    PRIMARY KEY (trn)
);
--Populate the table with some data
INSERT INTO #c
VALUES
(1, 'DD', '2011-12-23', NULL, 1500);
INSERT INTO #c
VALUES
(2, '1200', '2012-01-01', 'Car Leasing Company', -361.75);
INSERT INTO #c
VALUES
(3, '1201', '2012-01-01', 'Mortgage Bank', -1129.23);
INSERT INTO #c
VALUES
(4, 'DD', '2012-01-08', NULL, 1100);
INSERT INTO #c
VALUES
(5, '1202', '2012-01-15', 'Gas Company', -108.49);
INSERT INTO #c
VALUES
(6, '1203', '2012-01-15', 'Electric Company', -98.27);
INSERT INTO #c
VALUES
(7, '1204', '2012-01-15', 'Telephone Company', -136.6);
INSERT INTO #c
VALUES
(8, 'DD', '2012-02-15', NULL, 1100);
INSERT INTO #c
VALUES
(9, '1205', '2012-02-01', 'Car Leasing Company', -361.75);
INSERT INTO #c
VALUES
(10, '1206', '2012-02-01', 'Mortgage Bank', -1129.23);
INSERT INTO #c
VALUES
(11, 'DD', '2012-02-08', NULL, 1100);
INSERT INTO #c
VALUES
(12, '1207', '2012-02-15', 'Gas Company', -153.89);
INSERT INTO #c
VALUES
(13, '1208', '2012-02-15', 'Electric Company', -121.99);
INSERT INTO #c
VALUES
(14, '1209', '2012-02-15', 'Telephone Company', -138.92);
INSERT INTO #c
VALUES
(15, 'DD', '2012-02-23', NULL, 1100);
INSERT INTO #c
VALUES
(16, '1210', '2012-03-01', 'Car Leasing Company', -361.75);
INSERT INTO #c
VALUES
(17, '1211', '2012-03-01', 'Mortgage Bank', -1129.23);
INSERT INTO #c
VALUES
(18, 'DD', '2012-03-08', NULL, 1100);
INSERT INTO #c
VALUES
(19, '1212', '2012-03-15', 'Gas Company', -70.79);
INSERT INTO #c
VALUES
(20, '1213', '2012-03-15', 'Electric Company', -93.57);
INSERT INTO #c
VALUES
(21, '1214', '2012-03-15', 'Telephone Company', -149.78);
INSERT INTO #c
VALUES
(22, 'DD', '2012-03-23', NULL, 1100);
INSERT INTO #c
VALUES
(23, '1215', '2012-04-01', 'Car Leasing Company', -361.75);
INSERT INTO #c
VALUES
(24, '1216', '2012-04-01', 'Mortgage Bank', -1129.23);
INSERT INTO #c
VALUES
(25, 'DD', '2012-04-08', NULL, 1100);
INSERT INTO #c
VALUES
(26, '1217', '2012-04-15', 'Gas Company', -105.58);
INSERT INTO #c
VALUES
(27, '1218', '2012-04-15', 'Electric Company', -149.36);
INSERT INTO #c
VALUES
(28, '1219', '2012-04-15', 'Telephone Company', -145.35);
INSERT INTO #c
VALUES
(29, 'DD', '2012-04-23', NULL, 1100);
INSERT INTO #c
VALUES
(30, '1220', '2012-05-01', 'Car Leasing Company', -361.75);
INSERT INTO #c
VALUES
(31, '1221', '2012-05-01', 'Mortgage Bank', -1129.23);
INSERT INTO #c
VALUES
(32, 'DD', '2012-05-08', NULL, 1100);
INSERT INTO #c
VALUES
(33, '1222', '2012-05-15', 'Gas Company', -96.27);
INSERT INTO #c
VALUES
(34, '1223', '2012-05-15', 'Electric Company', -114.62);
INSERT INTO #c
VALUES
(35, '1224', '2012-05-15', 'Telephone Company', -145.43);
INSERT INTO #c
VALUES
(36, 'DD', '2012-05-23', NULL, 1100);
INSERT INTO #c
VALUES
(37, '1225', '2012-06-01', 'Car Leasing Company', -361.75);
INSERT INTO #c
VALUES
(38, '1226', '2012-06-01', 'Mortgage Bank', -1129.23);
INSERT INTO #c
VALUES
(39, 'DD', '2012-06-08', NULL, 1100);
INSERT INTO #c
VALUES
(40, '1227', '2012-06-15', 'Gas Company', -147.03);
INSERT INTO #c
VALUES
(41, '1228', '2012-06-15', 'Electric Company', -130.52);
INSERT INTO #c
VALUES
(42, '1229', '2012-06-15', 'Telephone Company', -147.71);
INSERT INTO #c
VALUES
(43, 'DD', '2012-06-23', NULL, 1100);
INSERT INTO #c
VALUES
(44, '1230', '2012-07-01', 'Car Leasing Company', -361.75);
INSERT INTO #c
VALUES
(45, '1231', '2012-07-01', 'Mortgage Bank', -1129.23);
INSERT INTO #c
VALUES
(46, 'DD', '2012-07-08', NULL, 1100);
--Calculate the running COUNT
SELECT cast(convert(varchar, date_trn, 106) as char(11)) as date_trn,
       cust_ref,
       payee,
       amt_trn,
       wct.RunningCOUNT(amt_trn, trn, NULL, NULL) as [Running Count]
FROM #c;
--Clean up
DROP TABLE #c;

This produces the following result.

In this example, we calculate the running count and the running count for each month and use the ROW_NUMBER() function to determine the @RowNum value passed into the RunningCOUNT function.

SELECT cast(convert(varchar, date_trn, 106) as char(11)) as date_trn,
       cust_ref,
       payee,
       amt_trn,
       wct.RunningCOUNT(amt_trn, ROW_NUMBER() OVER (PARTITION by MONTH(date_trn)
                 ORDER BY trn), 1, NULL) as [MTD Count],
       wct.RunningCOUNT(amt_trn, trn, NULL, NULL) as [Running Count]
FROM #c
ORDER BY trn;

This produces the following result.

In this Example we use a CASE statement and set @CountNulls to 'False' in order to count just the debits.

SELECT cast(convert(varchar, date_trn, 106) as char(11)) as date_trn,
       cust_ref,
       payee,
       amt_trn,
       wct.RunningCOUNT(   CASE
                               WHEN amt_trn > 0 THEN
                                   NULL
                               ELSE
                                   amt_trn
                           END,
                           ROW_NUMBER() OVER (PARTITION by MONTH(date_trn)ORDER 
                                     BY trn),
                           1,
                           'False'
                       ) as [MTD Count],
       wct.RunningCOUNT(   CASE
                               WHEN amt_trn > 0 THEN
                                   NULL
                               ELSE
                                   amt_trn
                           END,
                           trn,
                           NULL,
                           'False'
                       ) as [Running Count]
FROM #c
ORDER BY trn;

This produces the following result.