GROUPING_ID (Transact-SQL)

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance

GROUPING_ID Is a function that computes the level of grouping. GROUPING_ID can be used only in the SELECT <select> list, HAVING, or ORDER BY clauses when GROUP BY is specified.

Transact-SQL syntax conventions

Syntax

GROUPING_ID ( <column_expression> [ , ...n ] )

Arguments

<column_expression>

A column_expression in a SELECT - GROUP BY clause.

Return types

int

Remarks

The GROUPING_ID <column_expression> must exactly match the expression in the GROUP BY list. For example, if you're grouping by DATEPART (yyyy, <column name>), use GROUPING_ID (DATEPART (yyyy, <column name>)); or if you're grouping by <column name>, use GROUPING_ID (<column name>).

Compare GROUPING_ID() to GROUPING()

GROUPING_ID (<column_expression> [ , ...n ]) inputs the equivalent of the GROUPING (<column_expression>) return for each column in its column list in each output row, as a string of ones and zeros. GROUPING_ID interprets that string as a base-2 number and returns the equivalent integer.

For example, consider the following statement:

SELECT a, b, c, SUM(d),
GROUPING_ID(a, b, c)
FROM T
GROUP BY <group_by_list>

This table shows the GROUPING_ID() input and output values.

Technical definition of GROUPING_ID()

Each GROUPING_ID argument must be an element of the GROUP BY list. GROUPING_ID() returns an integer bitmap whose lowest n bits might be lit. A lit bit indicates the corresponding argument isn't a grouping column for the given output row. The lowest-order bit corresponds to argument n, and the n-1^th lowest-order bit corresponds to argument 1.

GROUPING_ID() equivalents

For a single grouping query, GROUPING (<column_expression>) is equivalent to GROUPING_ID (<column_expression>), and both return 0.

For example, the following statements are equivalent:

Statement A

SELECT GROUPING_ID(A, B)
FROM T
GROUP BY CUBE(A, B)

Statement B

SELECT 3 FROM T GROUP BY ()
UNION ALL
SELECT 1 FROM T GROUP BY A
UNION ALL
SELECT 2 FROM T GROUP BY B
UNION ALL
SELECT 0 FROM T GROUP BY A, B

Examples

The Transact-SQL code samples in this article use the AdventureWorks2022 or AdventureWorksDW2022 sample database, which you can download from the Microsoft SQL Server Samples and Community Projects home page.

A. Use GROUPING_ID to identify grouping levels

The following example returns the count of employees by Name and Title, and company total in the AdventureWorks2022 database. GROUPING_ID() is used to create a value for each row in the Title column that identifies its level of aggregation.

SELECT D.Name,
    CASE 
        WHEN GROUPING_ID(D.Name, E.JobTitle) = 0 THEN E.JobTitle
        WHEN GROUPING_ID(D.Name, E.JobTitle) = 1 THEN N'Total: ' + D.Name
        WHEN GROUPING_ID(D.Name, E.JobTitle) = 3 THEN N'Company Total:'
        ELSE N'Unknown'
    END AS N'Job Title',
    COUNT(E.BusinessEntityID) AS N'Employee Count'
FROM HumanResources.Employee E
INNER JOIN HumanResources.EmployeeDepartmentHistory DH
    ON E.BusinessEntityID = DH.BusinessEntityID
INNER JOIN HumanResources.Department D
    ON D.DepartmentID = DH.DepartmentID
WHERE DH.EndDate IS NULL
    AND D.DepartmentID IN (12, 14)
GROUP BY ROLLUP(D.Name, E.JobTitle);

B. Use GROUPING_ID to filter a result set

Basic example

In the following code, to return only the rows that have a count of employees by title, remove the comment characters from HAVING GROUPING_ID(D.Name, E.JobTitle) = 0;. To return only rows with a count of employees by department, remove the comment characters from HAVING GROUPING_ID(D.Name, E.JobTitle) = 1;.

SELECT D.Name,
    E.JobTitle,
    GROUPING_ID(D.Name, E.JobTitle) AS [Grouping Level],
    COUNT(E.BusinessEntityID) AS [Employee Count]
FROM HumanResources.Employee AS E
INNER JOIN HumanResources.EmployeeDepartmentHistory AS DH
    ON E.BusinessEntityID = DH.BusinessEntityID
INNER JOIN HumanResources.Department AS D
    ON D.DepartmentID = DH.DepartmentID
WHERE DH.EndDate IS NULL
    AND D.DepartmentID IN (12, 14)
GROUP BY ROLLUP(D.Name, E.JobTitle)
-- HAVING GROUPING_ID(D.Name, E.JobTitle) = 0; -- All titles
-- HAVING GROUPING_ID(D.Name, E.JobTitle) = 1; -- Group by Name;

Here's the unfiltered result set.

Complex example

The following example uses GROUPING_ID() to filter a result set that contains multiple grouping levels by grouping level. Similar code can be used to create a view that has several grouping levels, and a stored procedure that calls the view by passing a parameter that filters the view by grouping level.

DECLARE @Grouping NVARCHAR(50);
DECLARE @GroupingLevel SMALLINT;

SET @Grouping = N'CountryRegionCode Total';

SELECT @GroupingLevel = (
    CASE @Grouping
        WHEN N'Grand Total' THEN 15
        WHEN N'SalesPerson Total' THEN 14
        WHEN N'Store Total' THEN 13
        WHEN N'Store SalesPerson Total' THEN 12
        WHEN N'CountryRegionCode Total' THEN 11
        WHEN N'Group Total' THEN 7
        ELSE N'Unknown'
    END
);

SELECT T.[Group],
    T.CountryRegionCode,
    S.Name AS N'Store',
    (
        SELECT P.FirstName + ' ' + P.LastName
        FROM Person.Person AS P
        WHERE P.BusinessEntityID = H.SalesPersonID
    ) AS N'Sales Person',
    SUM(TotalDue) AS N'TotalSold',
    CAST(GROUPING(T.[Group]) AS CHAR(1)) + CAST(GROUPING(T.CountryRegionCode) AS CHAR(1)) + CAST(GROUPING(S.Name) AS CHAR(1)) + CAST(GROUPING(H.SalesPersonID) AS CHAR(1)) AS N'GROUPING base-2',
    GROUPING_ID((T.[Group]), (T.CountryRegionCode), (S.Name), (H.SalesPersonID)) AS N'GROUPING_ID',
    CASE 
        WHEN GROUPING_ID((T.[Group]), (T.CountryRegionCode), (S.Name), (H.SalesPersonID)) = 15
            THEN N'Grand Total'
        WHEN GROUPING_ID((T.[Group]), (T.CountryRegionCode), (S.Name), (H.SalesPersonID)) = 14
            THEN N'SalesPerson Total'
        WHEN GROUPING_ID((T.[Group]), (T.CountryRegionCode), (S.Name), (H.SalesPersonID)) = 13
            THEN N'Store Total'
        WHEN GROUPING_ID((T.[Group]), (T.CountryRegionCode), (S.Name), (H.SalesPersonID)) = 12
            THEN N'Store SalesPerson Total'
        WHEN GROUPING_ID((T.[Group]), (T.CountryRegionCode), (S.Name), (H.SalesPersonID)) = 11
            THEN N'CountryRegionCode Total'
        WHEN GROUPING_ID((T.[Group]), (T.CountryRegionCode), (S.Name), (H.SalesPersonID)) = 7
            THEN N'Group Total'
        ELSE N'Error'
    END AS N'Level'
FROM Sales.Customer AS C
INNER JOIN Sales.Store AS S
    ON C.StoreID = S.BusinessEntityID
INNER JOIN Sales.SalesTerritory AS T
    ON C.TerritoryID = T.TerritoryID
INNER JOIN Sales.SalesOrderHeader AS H
    ON C.CustomerID = H.CustomerID
GROUP BY GROUPING SETS(
    (S.Name,H.SalesPersonID),
    (H.SalesPersonID), 
    (S.Name), 
    (T.[Group]),
    (T.CountryRegionCode),
    ()
)
HAVING GROUPING_ID(
    (T.[Group]),
    (T.CountryRegionCode),
    (S.Name),
    (H.SalesPersonID)
) = @GroupingLevel
ORDER BY
    GROUPING_ID(S.Name, H.SalesPersonID),
    GROUPING_ID(
        (T.[Group]),
        (T.CountryRegionCode),
        (S.Name),
        (H.SalesPersonID)
    ) ASC;

C. Use GROUPING_ID() with ROLLUP and CUBE to identify grouping levels

The code in the following examples shows using GROUPING() to compute the Bit Vector(base-2) column. GROUPING_ID() is used to compute the corresponding Integer Equivalent column. The column order in the GROUPING_ID() function is the opposite of the column order of the columns that are concatenated by the GROUPING() function.

In these examples, GROUPING_ID() is used to create a value for each row in the Grouping Level column to identify the level of grouping. Grouping levels aren't always a consecutive list of integers that start with 1 (0, 1, 2, ...n).

ROLLUP example

In this example, all grouping levels don't appear as they do in the following CUBE example. If the order of the columns in the ROLLUP list is changed, the level values in the Grouping Level column also have to be changed.

SELECT DATEPART(yyyy, OrderDate) AS N'Year',
    DATEPART(mm, OrderDate) AS N'Month',
    DATEPART(dd, OrderDate) AS N'Day',
    SUM(TotalDue) AS N'Total Due',
    CAST(GROUPING(DATEPART(dd, OrderDate)) AS CHAR(1)) + CAST(GROUPING(DATEPART(mm, OrderDate)) AS CHAR(1)) + CAST(GROUPING(DATEPART(yyyy, OrderDate)) AS CHAR(1)) AS N'Bit Vector(base-2)',
    GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) AS N'Integer Equivalent',
    CASE 
        WHEN GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) = 0
            THEN N'Year Month Day'
        WHEN GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) = 1
            THEN N'Year Month'
        WHEN GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) = 2
            THEN N'not used'
        WHEN GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) = 3
            THEN N'Year'
        WHEN GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) = 4
            THEN N'not used'
        WHEN GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) = 5
            THEN N'not used'
        WHEN GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) = 6
            THEN N'not used'
        WHEN GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) = 7
            THEN N'Grand Total'
        ELSE N'Error'
    END AS N'Grouping Level'
FROM Sales.SalesOrderHeader
WHERE DATEPART(yyyy, OrderDate) IN (N'2007', N'2008')
    AND DATEPART(mm, OrderDate) IN (1, 2)
    AND DATEPART(dd, OrderDate) IN (1, 2)
GROUP BY ROLLUP(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate))
ORDER BY GROUPING_ID(DATEPART(mm, OrderDate), DATEPART(yyyy, OrderDate), DATEPART(dd, OrderDate)),
    DATEPART(yyyy, OrderDate),
    DATEPART(mm, OrderDate),
    DATEPART(dd, OrderDate);

Here's a partial result set.

CUBE example

In this example, the GROUPING_ID() function is used to create a value for each row in the Grouping Level column to identify the level of grouping.

Unlike ROLLUP in the previous example, CUBE outputs all grouping levels. If the order of the columns in the CUBE list is changed, the level values in the Grouping Level column also have to be changed.

SELECT DATEPART(yyyy, OrderDate) AS N'Year',
    DATEPART(mm, OrderDate) AS N'Month',
    DATEPART(dd, OrderDate) AS N'Day',
    SUM(TotalDue) AS N'Total Due',
    CAST(GROUPING(DATEPART(dd, OrderDate)) AS CHAR(1)) + CAST(GROUPING(DATEPART(mm, OrderDate)) AS CHAR(1)) + CAST(GROUPING(DATEPART(yyyy, OrderDate)) AS CHAR(1)) AS N'Bit Vector(base-2)',
    GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) AS N'Integer Equivalent',
    CASE 
        WHEN GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) = 0
            THEN N'Year Month Day'
        WHEN GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) = 1
            THEN N'Year Month'
        WHEN GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) = 2
            THEN N'Year Day'
        WHEN GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) = 3
            THEN N'Year'
        WHEN GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) = 4
            THEN N'Month Day'
        WHEN GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) = 5
            THEN N'Month'
        WHEN GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) = 6
            THEN N'Day'
        WHEN GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)) = 7
            THEN N'Grand Total'
        ELSE N'Error'
    END AS N'Grouping Level'
FROM Sales.SalesOrderHeader
WHERE DATEPART(yyyy, OrderDate) IN (N'2007', N'2008')
    AND DATEPART(mm, OrderDate) IN (1, 2)
    AND DATEPART(dd, OrderDate) IN (1, 2)
GROUP BY CUBE(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate))
ORDER BY GROUPING_ID(DATEPART(yyyy, OrderDate), DATEPART(mm, OrderDate), DATEPART(dd, OrderDate)),
    DATEPART(yyyy, OrderDate),
    DATEPART(mm, OrderDate),
    DATEPART(dd, OrderDate);

Here's a partial result set.

Related content

• GROUPING (Transact-SQL)
• SELECT - GROUP BY (Transact-SQL)