GREATEST

Syntax

Description of the illustration greatest.gif

Purpose

GREATEST returns the greatest of a list of one or more expressions. Oracle Database uses the first expr to determine the return type. If the first expr is numeric, then Oracle determines the argument with the highest numeric precedence, implicitly converts the remaining arguments to that data type before the comparison, and returns that data type. If the first expr is not numeric, then each expr after the first is implicitly converted to the data type of the first expr before the comparison.

Oracle Database compares each expr using nonpadded comparison semantics. The comparison is binary by default and is linguistic if the NLS_COMP parameter is set to LINGUISTIC and the NLS_SORT parameter has a setting other than BINARY. Character comparison is based on the numerical codes of the characters in the database character set and is performed on whole strings treated as one sequence of bytes, rather than character by character. If the value returned by this function is character data, then its data type is VARCHAR2 if the first expr is a character data type and NVARCHAR2 if the first expr is a national character data type.

Examples

The following statement selects the string with the greatest value:

SELECT GREATEST('HARRY', 'HARRIOT', 'HAROLD') "Greatest"
  FROM DUAL;
 
Greatest
--------
HARRY

In the following statement, the first argument is numeric. Oracle Database determines that the argument with the highest numeric precedence is the second argument, converts the remaining arguments to the data type of the second argument, and returns the greatest value as that data type:

SELECT GREATEST (1, '3.925', '2.4') "Greatest"
  FROM DUAL;

Greatest
--------
   3.925