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MAX (Transact-SQL)

  • Artikkeli

Returns the maximum value in the expression. May be followed by the OVER clause.

Topic link iconTransact-SQL Syntax Conventions

Syntax

MAX ( [ ALL | DISTINCT ] expression )

Arguments

  • 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 SQL-92 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, and datetime columns, but not with bit columns. Aggregate functions and subqueries are not permitted.

    For more information, see Expressions (Transact-SQL).

Return Types

Returns a value same as expression.

Important

Distinct aggregates, for example AVG(DISTINCT column_name), COUNT(DISTINCT column_name), MAX(DISTINCT column_name), MIN(DISTINCT column_name), and SUM(DISTINCT column_name), are not supported when you use CUBE or ROLLUP. If they are used, Microsoft SQL Server 2005 Database Engine returns an error message and cancels the query.

Remarks

MAX ignores any null values.

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

Examples

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

USE AdventureWorks;
GO
SELECT MAX(TaxRate)
FROM Sales.SalesTaxRate;
GO

Here is the result set.

------
19.60

(1 row(s) affected)

Warning, null value eliminated from aggregate.

See Also

Reference

Aggregate Functions (Transact-SQL)
OVER Clause (Transact-SQL)

Help and Information

Getting SQL Server 2005 Assistance