MySQL Function Reference

TRUNCATE
Returns a number rounded to the specified number of decimal places by discarding subsequent digits.
MySQL 8.1
TRUNCATE(num, decimals)
num
Initial fractional number
decimals
Number of decimal places to round a number
The number of decimal places can be positive or negative and, at the same time, no more than 30 (or -30, in case of a negative value). If it is negative, then the digits to the left of the decimal point of num become zero, and the fractional part is truncated.
Examples
MySQL 8.1
SELECT TRUNCATE(22.29, 0);
MySQL 8.1
SELECT TRUNCATE(22.29, 1);
MySQL 8.1
SELECT TRUNCATE(22.29, -1);