public void Abs()
{
var value = SqlExpression.Constant(Field.Number(new SqlNumber(-45636.0003922)));
var result = Select("ABS", value);
Assert.IsNotNull(result);
Assert.IsFalse(Field.IsNullField(result));
Assert.IsInstanceOf<NumericType>(result.Type);
Assert.IsInstanceOf<SqlNumber>(result.Value);
var number = ((SqlNumber)result.Value).ToDouble();
Assert.AreEqual(45636.0003922, number);
}