mysql function returns DECIMAL code example

Example 1: mysql decimal allow negative values?

/*
Negative values are allowed as long as the field is not specified to be unsigned.

Standard SQL requires that DECIMAL(5,2) be able to store any value with five digits and two decimals,
so values that can be stored in the salary column range from -999.99 to 999.99
*/

Example 2: round one decimal place mysql

SELECT ROUND(20.555, 1);
-- 20.5
SELECT ROUND(20.5, 0);
-- 21