| title | MAX (Transact-SQL) | Microsoft Docs | |||
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| ms.custom | ||||
| ms.date | 03/13/2017 | |||
| ms.prod | sql-non-specified | |||
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| ms.tgt_pltfrm | ||||
| ms.topic | language-reference | |||
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| ms.assetid | 9b002b69-ab5e-472d-b12e-dc2fbe35ef42 | |||
| caps.latest.revision | 38 | |||
| author | BYHAM | |||
| ms.author | rickbyh | |||
| manager | jhubbard |
[!INCLUDEtsql-appliesto-ss2008-all_md]
Returns the maximum value in the expression.
Transact-SQL Syntax Conventions
-- Syntax for SQL Server and Azure SQL Database
MAX ( [ ALL | DISTINCT ] expression )
OVER ( [ partition_by_clause ] order_by_clause )
-- Syntax for Azure SQL Data Warehouse and Parallel Data Warehouse
-- Aggregation Function Syntax
MAX ( [ ALL | DISTINCT ] expression )
-- Aggregation Function Syntax
MAX ( expression ) OVER ( [ <partition_by_clause> ] [ <order_by_clause> ] )
ALL
Applies the aggregate function to all values. ALL is the default.
DISTINCT
Specifies that each unique value is considered. DISTINCT is not meaningful with MAX and is available for ISO compatibility only.
expression
Is a constant, column name, or function, and any combination of arithmetic, bitwise, and string operators. MAX can be used with numeric, character, uniqueidentifier, and datetime columns, but not with bit columns. Aggregate functions and subqueries are not permitted.
For more information, see Expressions (Transact-SQL).
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. order_by_clause is required. For more information, see OVER Clause (Transact-SQL).
Returns a value same as expression.
MAX ignores any null values.
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 is nondeterministic when specified with the OVER and ORDER BY clauses. For more information, see Deterministic and Nondeterministic Functions.
The following example returns the highest (maximum) tax rate in the [!INCLUDEssSampleDBnormal] database.
SELECT MAX(TaxRate)
FROM Sales.SalesTaxRate;
GO
[!INCLUDEssResult]
-------------------
19.60
Warning, null value eliminated from aggregate.
(1 row(s) affected)
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 in the [!INCLUDEssSampleDBnormal] database.
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
JOIN HumanResources.EmployeeDepartmentHistory AS edh
ON eph.BusinessEntityID = edh.BusinessEntityID
JOIN HumanResources.Department AS d
ON d.DepartmentID = edh.DepartmentID
WHERE edh.EndDate IS NULL
ORDER BY Name;
[!INCLUDEssResult]
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
(16 row(s) affected)
The following example uses the MAX aggregate function to return the price of the most expensive (maximum) product in a specified set of sales orders.
-- Uses AdventureWorks
SELECT DISTINCT MAX(UnitPrice)
FROM dbo.FactResellerSales
WHERE SalesOrderNumber IN (N'SO43659', N'SO43660', N'SO43664');
[!INCLUDEssResult]
----------
2039.9940
The following examples use the MAX OVER() analytic function to return the price of the most expensive product in each sales order.
-- Uses AdventureWorks
SELECT DISTINCT MAX(UnitPrice) OVER(PARTITION BY SalesOrderNumber) AS MostExpensiveProduct,
SalesOrderNumber
FROM dbo.FactResellerSales
WHERE SalesOrderNumber IN (N'SO43659', N'SO43660', N'SO43664')
ORDER BY SalesOrderNumber
;
[!INCLUDEssResult]
MostExpensiveProduct SalesOrderNumber
--------------------- ----------------
2039.9940 SO43659
879.7940 SO43660
2039.9940 SO43664
Aggregate Functions (Transact-SQL)
OVER Clause (Transact-SQL)