improved sql parser.

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/ast/SQLServerSelectQueryBlock.java

@@ -15,6 +15,8 @@
  */
 package com.alibaba.druid.sql.dialect.sqlserver.ast;
 
+import com.alibaba.druid.sql.ast.SQLLimit;
+import com.alibaba.druid.sql.ast.expr.SQLIntegerExpr;
 import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
 import com.alibaba.druid.sql.dialect.sqlserver.visitor.SQLServerASTVisitor;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
@@ -34,6 +36,10 @@ public class SQLServerSelectQueryBlock extends SQLSelectQueryBlock {
         this.top = top;
     }
 
+    public void setTop(int rowCount) {
+        setTop(new SQLServerTop(new SQLIntegerExpr(rowCount)));
+    }
+
     @Override
     protected void accept0(SQLASTVisitor visitor) {
         accept0((SQLServerASTVisitor) visitor);
@@ -49,4 +55,12 @@ public class SQLServerSelectQueryBlock extends SQLSelectQueryBlock {
         }
         visitor.endVisit(this);
     }
+
+    public void limit(int rowCount, int offset) {
+        if (offset <= 0) {
+            setTop(rowCount);
+        } else {
+            throw new UnsupportedOperationException("not support offset");
+        }
+    }
 }