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Applies to: 
SQL Server
Azure SQL Database
Azure SQL Managed Instance
Azure Synapse Analytics
Analytics Platform System (PDW)
SQL analytics endpoint in Microsoft Fabric
Warehouse in Microsoft Fabric
Returns the maximum of all values of the specified expression in a group. Can be followed by the OVER clause.
Note
To get the maximum of all values of multiple expressions inline, see Logical functions - GREATEST.
Transact-SQL syntax conventions
Syntax
Aggregation function syntax:
MAX ( [ ALL | DISTINCT ] expression )
Analytic function syntax:
MAX ( [ ALL ] expression) OVER ( [ <partition_by_clause> ] [ <order_by_clause> ] )
Arguments
ALL
Applies the aggregate function to all values. ALL is the default.
DISTINCT
Specifies that each unique value is considered. DISTINCT isn't meaningful with MAX, and is available for ISO compatibility only.
expression
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.
OVER ( [ partition_by_clause ] [ order_by_clause ] )
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.
Return types
Returns a value same as expression.
Remarks
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.
Examples
The 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. Basic example
The following example returns the highest (maximum) tax rate.
SELECT MAX(TaxRate)
FROM Sales.SalesTaxRate;
GO
Here's the result set.
-------------------
19.60
Warning, null value eliminated from aggregate.
B. Use the OVER clause
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;
Here's the result set.
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
C. Use MAX with character data
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.