code: func (s *SelectStatement) HasFieldWildcard() (hasWildcard bool) {
  	WalkFunc(s.Fields, func(n Node) {
  		if hasWildcard {
  			return
  		}
  		switch n.(type) {
  		case *Wildcard, *RegexLiteral:
  			hasWildcard = true
  		}
  	})
  	return hasWildcard
  }
docs: // HasFieldWildcard returns whether or not the select statement has at least 1 wildcard in the fields.