Enable comments in SQL code

sql/parser.go

@@ -196,8 +196,12 @@ func (p *Parser) unscan() { p.buf.n = 1 }
 // scanIgnoreWhitespace scans the next non-whitespace token.
 func (p *Parser) scanIgnoreWhitespace() (tok Token, lit string) {
 	tok, lit = p.scan()
-	if tok == WS {
-		tok, lit = p.scan()
+	for {
+		if tok == WS {
+			tok, lit = p.scan()
+		} else {
+			break
+		}
 	}
 	return
 }

sql/scanner.go

@@ -106,6 +106,14 @@ func (s *Scanner) Scan() (tok Token, lit string) {
 	case '-':
 		if chn := s.read(); chn == '>' {
 			return OEDGE, "->"
+	case '/':
+		chn := s.next()
+		switch {
+		case chn == '*':
+			return s.scanCommentMultiple(ch)
+		default:
+			s.unread()
+			return s.scanRegexp(ch)
 		}
 		s.unread()
 		if chn := s.read(); chn == '=' {