How do you use the MySQL GREATEST function?

The GREATEST function in MySQL is used to return the maximum value from a set of values. It takes multiple parameters and returns the highest value among them.

The syntax for using the GREATEST function is as follows:

GREATEST(value1, value2, ...)

Value1, value2, etc. are the values to be compared.

Here is an example using the GREATEST function:

SELECT GREATEST(10, 5, 15, 20);

This query will return 20, as 20 is the largest value among the parameters passed to the GREATEST function.

You can also pass column names as parameters to the GREATEST function.

SELECT GREATEST(column1, column2, column3) FROM table;

This will return the maximum values from columns column1, column2, and column3 in the table.

It should be noted that the GREATEST function returns the maximum value among the parameters passed to it, rather than the maximum value in the entire table. If you want to find the maximum value in the entire table, you can use the MAX function.