odps sql parser improved comment support

src/main/java/com/alibaba/druid/sql/dialect/mysql/parser/MySqlLexer.java

@@ -22,7 +22,6 @@ import static com.alibaba.druid.sql.parser.Token.LITERAL_CHARS;
 import java.util.HashMap;
 import java.util.Map;
 
-import com.alibaba.druid.sql.parser.CharTypes;
 import com.alibaba.druid.sql.parser.Keywords;
 import com.alibaba.druid.sql.parser.Lexer;
 import com.alibaba.druid.sql.parser.NotAllowCommentException;
@@ -512,9 +511,28 @@ public class MySqlLexer extends Lexer {
             return;
         }
     }
+    
+    private final static boolean[] identifierFlags = new boolean[256];
+    static {
+        for (char c = 0; c < identifierFlags.length; ++c) {
+            if (c >= 'A' && c <= 'Z') {
+                identifierFlags[c] = true;
+            } else if (c >= 'a' && c <= 'z') {
+                identifierFlags[c] = true;
+            } else if (c >= '0' && c <= '9') {
+                identifierFlags[c] = true;
+            }
+        }
+        // identifierFlags['`'] = true;
+        identifierFlags['_'] = true;
+        identifierFlags['-'] = true; // mysql
+    }
 
-    private boolean isIdentifierChar(char c) {
-        return c != '#' && CharTypes.isIdentifierChar(c);
+    public static boolean isIdentifierChar(char c) {
+        if (c <= identifierFlags.length) {
+            return identifierFlags[c];
+        }
+        return false;
     }
 
     public void scanNumber() {

src/main/java/com/alibaba/druid/sql/dialect/odps/parser/OdpsCreateTableParser.java

@@ -73,6 +73,10 @@ public class OdpsCreateTableParser extends SQLCreateTableParser {
         } else {
             accept(Token.LPAREN);
             
+            if (lexer.isKeepComments() && lexer.hasComment()) {
+                stmt.addBodyBeforeComment(lexer.readAndResetComments());
+            }
+            
             for (;;) {
                 if (lexer.token() != Token.IDENTIFIER) {
                     throw new ParserException("expect identifier");

src/main/java/com/alibaba/druid/sql/dialect/odps/visitor/OdpsOutputVisitor.java

@@ -96,6 +96,12 @@ public class OdpsOutputVisitor extends SQLASTOutputVisitor implements OdpsASTVis
         int size = x.getTableElementList().size();
         if (size > 0) {
             print0(" (");
+            
+            if (this.isPrettyFormat() && x.hasBodyBeforeComment()) {
+                print(' ');
+                printComment(x.getBodyBeforeCommentsDirect(), "");
+            }
+            
             incrementIndent();
             println();
             for (int i = 0; i < size; ++i) {