code: func (b *builtinCeilDecToIntSig) evalInt(row chunk.Row) (int64, bool, error) {
  	val, isNull, err := b.args[0].EvalDecimal(b.ctx, row)
  	if isNull || err != nil {
  		return 0, isNull, err
  	}
  	// err here will only be ErrOverFlow(will never happen) or ErrTruncate(can be ignored).
  	res, err := val.ToInt()
  	if err == types.ErrTruncated {
  		err = nil
  		if !val.IsNegative() {
  			res = res + 1
  		}
  	}
  	return res, false, err
  }
docs: // evalInt evals a builtinCeilDecToIntSig.
  // Ceil receives