In Teradata Max function is used to get maximum value for a value_expression.
MAXIMUM([TYPE] value_expression) [Teradata extension to the ANSI SQL:2011 standard] MAX([TYPE] value_expression)
Where value_expression is a literal or column expression for which the maximum value is to be computed. The expression cannot contain any ordered analytical or aggregate functions.
TYPE as ALL => that all non-null values specified by value_expression, including duplicates, are included in the maximum value computation for the group. This is the default.
TYPE as DISTINCT => that duplicate and non-null values specified by value_expression are eliminated from the maximum value computation for the group.
MAX is valid for character data as well as numeric data. When used with a character expression, MAX returns the highest sort order. Nulls are not included in the result computation.
Example of Teradata Max: CHARACTER Data
The following SELECT returns the immediately following result.
SELECT MAX(Name) FROM Employee;
Maximum(Name) ------------- Zorn J
Example of Teradata Max: Column Expressions
You want to know which item in your warehouse stock has the maximum cost of sales.
SELECT MAX(CostOfSales) AS m, ProdID FROM Inventory GROUP BY ProdID ORDER BY m DESC;
Maximum(CostOfSales) ProdID -------------------- ------ 1295 3815 975 4400 950 4120