The FLOOR(x) function takes a number and returns the first integer that is less than or equal to the argument:
FLOOR(5.5) === FLOOR(5.1) === FLOOR(5) === 5 FLOOR(-5.5) === FLOOR(-5.1) === FLOOR(-6) === -6
The FLOOR() function (v11.0+) takes a second optional parameter to indicate the number of decimal digits to operate to:
FLOOR(5.6789,2) === 5.67 FLOOR(-5.6789,2) === -5.68