improve sql parser, sql server support with

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/parser/SQLServerLexer.java

@@ -15,11 +15,14 @@
  */
 package com.alibaba.druid.sql.dialect.sqlserver.parser;
 
+import static com.alibaba.druid.sql.parser.LayoutCharacters.EOI;
+
 import java.util.HashMap;
 import java.util.Map;
 
 import com.alibaba.druid.sql.parser.Keywords;
 import com.alibaba.druid.sql.parser.Lexer;
+import com.alibaba.druid.sql.parser.NotAllowCommentException;
 import com.alibaba.druid.sql.parser.Token;
 
 public class SQLServerLexer extends Lexer {
@@ -48,4 +51,95 @@ public class SQLServerLexer extends Lexer {
         super(input);
         super.keywods = DEFAULT_SQL_SERVER_KEYWORDS;
     }
+    
+    public void scanComment() {
+        if (ch != '/' && ch != '-') {
+            throw new IllegalStateException();
+        }
+
+        mark = pos;
+        bufPos = 0;
+        scanChar();
+
+        // /*+ */
+        if (ch == '*') {
+            scanChar();
+            bufPos++;
+
+            while (ch == ' ') {
+                scanChar();
+                bufPos++;
+            }
+
+            boolean isHint = false;
+            int startHintSp = bufPos + 1;
+            if (ch == '!') {
+                isHint = true;
+                scanChar();
+                bufPos++;
+            }
+
+            for (;;) {
+                if (ch == '*' && charAt(pos + 1) == '/') {
+                    bufPos += 2;
+                    scanChar();
+                    scanChar();
+                    break;
+                }
+
+                scanChar();
+                bufPos++;
+            }
+
+            if (isHint) {
+                stringVal = subString(mark + startHintSp, (bufPos - startHintSp) - 1);
+                token = Token.HINT;
+            } else {
+                stringVal = subString(mark, bufPos);
+                token = Token.MULTI_LINE_COMMENT;
+            }
+
+            if (token != Token.HINT && !isAllowComment()) {
+                throw new NotAllowCommentException();
+            }
+
+            return;
+        }
+
+        if (!isAllowComment()) {
+            throw new NotAllowCommentException();
+        }
+
+        if (ch == '/' || ch == '-') {
+            scanChar();
+            bufPos++;
+
+            for (;;) {
+                if (ch == '\r') {
+                    if (charAt(pos + 1) == '\n') {
+                        bufPos += 2;
+                        scanChar();
+                        break;
+                    }
+                    bufPos++;
+                    break;
+                } else if (ch == EOI) {
+                    break;
+                }
+
+                if (ch == '\n') {
+                    scanChar();
+                    bufPos++;
+                    break;
+                }
+
+                scanChar();
+                bufPos++;
+            }
+
+            stringVal = subString(mark + 1, bufPos);
+            token = Token.LINE_COMMENT;
+            return;
+        }
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/parser/SQLServerSelectParser.java

@@ -37,6 +37,8 @@ public class SQLServerSelectParser extends SQLSelectParser {
 
     public SQLSelect select()  {
         SQLServerSelect select = new SQLServerSelect();
+        
+        withSubquery(select);
 
         select.setQuery(query());
         select.setOrderBy(parseOrderBy());

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/parser/SQLServerStatementParser.java

@@ -15,6 +15,8 @@
  */
 package com.alibaba.druid.sql.dialect.sqlserver.parser;
 
+import java.util.List;
+
 import com.alibaba.druid.sql.ast.SQLName;
 import com.alibaba.druid.sql.ast.SQLStatement;
 import com.alibaba.druid.sql.ast.expr.SQLQueryExpr;
@@ -40,6 +42,16 @@ public class SQLServerStatementParser extends SQLStatementParser {
         super(new SQLServerExprParser(lexer));
     }
     
+    public boolean parseStatementListDialect(List<SQLStatement> statementList) {
+        if (lexer.token() == Token.WITH) {
+            SQLStatement stmt = parseSelect();
+            statementList.add(stmt);
+            return true;
+        }
+
+        return false;
+    }
+    
     public SQLStatement parseInsert() {
         SQLServerInsertStatement insertStatement = new SQLServerInsertStatement();
 

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

@@ -38,6 +38,7 @@ import com.alibaba.druid.sql.ast.statement.SQLInsertStatement;
 import com.alibaba.druid.sql.ast.statement.SQLReleaseSavePointStatement;
 import com.alibaba.druid.sql.ast.statement.SQLRollbackStatement;
 import com.alibaba.druid.sql.ast.statement.SQLSavePointStatement;
+import com.alibaba.druid.sql.ast.statement.SQLSelect;
 import com.alibaba.druid.sql.ast.statement.SQLSelectStatement;
 import com.alibaba.druid.sql.ast.statement.SQLSetStatement;
 import com.alibaba.druid.sql.ast.statement.SQLTableSource;
@@ -80,7 +81,7 @@ public class SQLStatementParser extends SQLParser {
                 continue;
             }
 
-            if (lexer.token() == (Token.SELECT)) {
+            if (lexer.token() == Token.SELECT) {
                 statementList.add(parseSelect());
                 continue;
             }
@@ -545,7 +546,9 @@ public class SQLStatementParser extends SQLParser {
     }
 
     public SQLSelectStatement parseSelect() {
-        return new SQLSelectStatement(createSQLSelectParser().select());
+        SQLSelectParser selectParser = createSQLSelectParser();
+        SQLSelect select = selectParser.select();
+        return new SQLSelectStatement(select);
     }
 
     public SQLSelectParser createSQLSelectParser() {