The ABS function returns the positive value of a negative number. The return data type is the data type of the input parameter. The ABS function has no effect on 0 and positive numbers.
Below you can see how the ABS function behaves at different values.
1 2 3 4 5 6 | SELECT ABS(0.3), ABS(0.234234), ABS(-1213), ABS(0.0), ABS(-0.999), ABS(0) |