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Returns the maximum of all values of the specified expression in a group. Can be followed by the OVER clause.

:::image type="icon" source="../../includes/media/topic-link-icon.svg" border="false"::: Transact-SQL syntax conventions

Aggregation function syntax:

MAX ( [ ALL | DISTINCT ] expression )

Analytic function syntax:

MAX ( [ ALL ] expression) OVER ( [ <partition_by_clause> ] [ <order_by_clause> ] )

Applies the aggregate function to all values. ALL is the default.

Specifies that each unique value is considered. DISTINCT isn't meaningful with MAX, and is available for ISO compatibility only.

A constant, column name, or function, and any combination of arithmetic, bitwise, and string operators. MAX can be used with numeric, char, nchar, varchar, nvarchar, uniqueidentifier, or datetime columns, but not with bit columns. Aggregate functions and subqueries aren't permitted.

For more information, see Expressions.

partition_by_clause divides the result set produced by the FROM clause into partitions to which the function is applied. If not specified, the function treats all rows of the query result set as a single group.

order_by_clause determines the logical order in which the operation is performed.

For more information, see SELECT - OVER clause.

Returns a value same as expression.

MAX ignores any null values.

MAX returns NULL when there's no row to select.

For character columns, MAX finds the highest value in the collating sequence.

MAX is a deterministic function when used without the OVER and ORDER BY clauses. It's nondeterministic when specified with the OVER and ORDER BY clauses. For more information, see Deterministic and nondeterministic functions.

MAX operates on a set of rows. To obtain the maximum value for a set of values inline, see Logical functions - GREATEST.

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The following example returns the highest (maximum) tax rate.

SELECT MAX(TaxRate)
FROM Sales.SalesTaxRate;
GO

[!INCLUDE ssResult]

-------------------
19.60
Warning, null value eliminated from aggregate.

The following example uses the MIN, MAX, AVG, and COUNT functions with the OVER clause to provide aggregated values for each department in the HumanResources.Department table.

SELECT DISTINCT Name,
                MIN(Rate) OVER (PARTITION BY edh.DepartmentID) AS MinSalary,
                MAX(Rate) OVER (PARTITION BY edh.DepartmentID) AS MaxSalary,
                AVG(Rate) OVER (PARTITION BY edh.DepartmentID) AS AvgSalary,
                COUNT(edh.BusinessEntityID) OVER (PARTITION BY edh.DepartmentID) AS EmployeesPerDept
FROM HumanResources.EmployeePayHistory AS eph
     INNER JOIN HumanResources.EmployeeDepartmentHistory AS edh
         ON eph.BusinessEntityID = edh.BusinessEntityID
     INNER JOIN HumanResources.Department AS d
         ON d.DepartmentID = edh.DepartmentID
WHERE edh.EndDate IS NULL
ORDER BY Name;

[!INCLUDE ssResult]

Name                          MinSalary             MaxSalary             AvgSalary             EmployeesPerDept
----------------------------- --------------------- --------------------- --------------------- ----------------
Document Control              10.25                 17.7885               14.3884               5
Engineering                   32.6923               63.4615               40.1442               6
Executive                     39.06                 125.50                68.3034               4
Facilities and Maintenance    9.25                  24.0385               13.0316               7
Finance                       13.4615               43.2692               23.935                10
Human Resources               13.9423               27.1394               18.0248               6
Information Services          27.4038               50.4808               34.1586               10
Marketing                     13.4615               37.50                 18.4318               11
Production                    6.50                  84.1346               13.5537               195
Production Control            8.62                  24.5192               16.7746               8
Purchasing                    9.86                  30.00                 18.0202               14
Quality Assurance             10.5769               28.8462               15.4647               6
Research and Development      40.8654               50.4808               43.6731               4
Sales                         23.0769               72.1154               29.9719               18
Shipping and Receiving        9.00                  19.2308               10.8718               6
Tool Design                   8.62                  29.8462               23.5054               6

The following example returns the database name that sorts using the database name alphabetically. The example uses WHERE database_id < 5, to select the system databases.

SELECT MAX(name)
FROM sys.databases
WHERE database_id < 5;

The last system database is tempdb.

• Aggregate Functions (Transact-SQL)
• Logical functions - GREATEST (Transact-SQL)
• SELECT - OVER clause (Transact-SQL)