code: func (b *builtinFromUnixTime1ArgSig) evalTime(row chunk.Row) (res types.Time, isNull bool, err error) {
  	return evalFromUnixTime(b.ctx, b.tp.Decimal, row, b.args[0])
  }
docs: // evalTime evals a builtinFromUnixTime1ArgSig.
  // See https://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_from-unixtime