MySQL Greatest function

The first few days of encountering a requirement is to take the maximum value out of the three columns,

Thought for a long time did not think out.

So I checked the next.

MySQL provides both greatest and LEAST with N parameters, and returns the maximum and minimum values, respectively.

The following description GREATEST and LEAST syntax of the function:

Greatest (Value1, value2, ...); LEAST (Value1,value2,...);

Parameters may have mixed data types. The following comparison rules apply to these two functions:

• If any parameter is NULL, then two functions are returned immediately NULL without any comparison.
• If you use a function in an int or REAL context, or if all parameters are integer values or REAL values, they are compared as INT and REAL to each.
• If the argument consists of a number and a string, the function compares them as numbers.
• If at least one parameter is a non-binary (character) string, the function compares the argument as a non-binary string.
• In all other cases, the function compares the arguments as a binary string

MySQL Greatest function