improved sql parser for sqlserver, support for xml clause

src/main/java/com/alibaba/druid/sql/ast/statement/SQLObjectType.java

@@ -1,5 +1,5 @@
 package com.alibaba.druid.sql.ast.statement;
 
 public enum SQLObjectType {
-    TABLE, FUNCTION, PROCEDURE, USER
+    TABLE, FUNCTION, PROCEDURE, USER, DATABASE
 }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLSelect.java

@@ -29,7 +29,7 @@ public class SQLSelect extends SQLObjectImpl {
     protected SQLSelectQuery        query;
     protected SQLOrderBy            orderBy;
 
-    private List<SQLHint>           hints;
+    protected List<SQLHint>           hints;
 
     public SQLSelect(){