MySQL GREATEST() Function

The GREATEST() function in MySQL is used to return the greatest (largest) value from a list of arguments. It evaluates each argument and returns the one with the highest value.

Syntax

GREATEST(arg1, arg2, arg3, ...)

Definition and Usage

• The GREATEST() function compares two or more values and returns the largest value in the list.
• If any argument is NULL, the result will be NULL.
• The function works for numeric, string, and date types, but the comparison is done based on the data type and the values' order.

Parameter Values

Technical Details

• Works in: From MySQL 4.0
• Return Value: The greatest value from the list of arguments.

Examples

Example 1: Return the greatest value of a list of numbers

SELECT GREATEST(3, 12, 34, 8, 25);

Result:

GREATEST(3, 12, 34, 8, 25): 34

Explanation: The function returns 34, which is the largest number in the list.

Example 2: Return the greatest value from a list of strings

SELECT GREATEST("w3Schools.com", "microsoft.com", "apple.com");

Result:

GREATEST("w3Schools.com", "microsoft.com", "apple.com"): "w3Schools.com"

Explanation: The function compares the strings lexicographically (alphabetically) and returns "w3Schools.com" as it comes last in alphabetical order.

Example 3: Return the greatest date value

SELECT GREATEST('2024-12-01', '2024-12-15', '2024-12-10');

Result:

GREATEST('2024-12-01', '2024-12-15', '2024-12-10'): '2024-12-15'

Explanation: The function returns '2024-12-15' as it is the latest date.

Usage Notes

• The GREATEST() function is useful for selecting the maximum value from multiple expressions or columns.
• When dealing with strings, it compares them in lexicographical order.
• For date values, the function returns the latest date.
• If any argument is NULL, the result will be NULL, so it's often good practice to ensure that NULL values are handled properly using IFNULL() or COALESCE().

This function is commonly used for finding the highest value in a set of values, such as finding the maximum salary, date, or number from a collection of records.