code: func StrToUint(sc *stmtctx.StatementContext, str string) (uint64, error) {
  	str = strings.TrimSpace(str)
  	validPrefix, err := getValidIntPrefix(sc, str)
  	if validPrefix[0] == '+' {
  		validPrefix = validPrefix[1:]
  	}
  	uVal, err1 := strconv.ParseUint(validPrefix, 10, 64)
  	if err1 != nil {
  		return uVal, ErrOverflow.GenWithStackByArgs("BIGINT UNSIGNED", validPrefix)
  	}
  	return uVal, errors.Trace(err)
  }
docs: // StrToUint converts a string to an unsigned integer at the best-effortt.