GROUPING_ID (Transact-SQL)

**APPLIES TO:** SQL Server (starting with 2008) Azure SQL Database Azure SQL Data Warehouse Parallel Data Warehouse

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>
Is a column_expression in a GROUP BY clause.

Return Type

int

Remarks

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

Comparing 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>. The following 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 may be lit. A lit bit indicates the corresponding argument is not 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

A. Using GROUPING_ID to identify grouping levels

The following example returns the count of employees by Name and Title, Name, and company total in the AdventureWorks2012 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. Using GROUPING_ID to filter a result set

Simple 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 in the AdventureWorks2012 database. 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 N'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 is 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. The example uses the AdventureWorks2012 database.

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

The code in the following examples show 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 are not always a consecutive list of integers that start with 1 (0, 1, 2,…n).

[!NOTE]
GROUPING and GROUPING_ID can be used n a HAVING clause to filter a result set.

ROLLUP Example

In this example, all grouping levels do not 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 will also have to be changed. The example uses the AdventureWorks2012 database.

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 is 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 will also have to be changed. The example uses the AdventureWorks2012 database

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 is a partial result set.

See Also

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