presto-main/src/main/java/io/prestosql/operator/scalar/MathFunctions.java/MathFunctions/absInteger
class MathFunctions:    @Description("absolute value")
    @ScalarFunction("abs")
    @SqlType(StandardTypes.INTEGER)
    public static long absInteger(@SqlType(StandardTypes.INTEGER) long num)
    {
        checkCondition(num != Integer.MIN_VALUE, NUMERIC_VALUE_OUT_OF_RANGE, "Value -2147483648 is out of range for abs(integer)");
        return Math.abs(num);
    }