In MySQL, the ATAN2() function returns the arc tangent of two values.
You provide the two values as comma-separated arguments when calling the function.
In MySQL, the CRC32() function computes a cyclic redundancy check value and returns a 32-bit unsigned value.
CRC stands for Cyclic Redundancy Check. A CRC is an error-detecting code commonly used in digital networks and storage devices to detect accidental changes to raw data (although, it doesn’t necessarily guard against malicious or intentional changes).
In MySQL, the ABS() function returns the absolute value of a given value.
An absolute value is the distance of a number on the number line from 0 without considering which direction from zero the number lies. Therefore, the absolute value of a number is always a non-negative value (i.e. it’s never negative).