bug fixed sql parser, support column name is 'comment'

pom.xml

@@ -17,7 +17,7 @@
 		<junit.version>4.11</junit.version>
 
 		<gpg.skip>true</gpg.skip>
-                <javadoc.skip>true</javadoc.skip>
+	        <javadoc.skip>true</javadoc.skip>
 
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 		<jdk.version>1.6</jdk.version>
@@ -88,8 +88,8 @@
 				<version>3.0</version>
 				<configuration>
 					<encoding>UTF-8</encoding>
-					<source>1.6</source>
-					<target>1.6</target>
+					<source>${jdk.version}</source>
+					<target>${jdk.version}</target>
 				</configuration>
 			</plugin>
 

src/main/java/com/alibaba/druid/sql/parser/SQLExprParser.java

@@ -226,6 +226,7 @@ public class SQLExprParser extends SQLParser {
             case COLUMN:
             case IF:
             case END:
+            case COMMENT:
                 sqlExpr = new SQLIdentifierExpr(lexer.stringVal());
                 lexer.nextToken();
                 break;