PageUtils SQL Server support

src/main/java/com/alibaba/druid/sql/ast/SQLOrderBy.java

@@ -29,6 +29,12 @@ public class SQLOrderBy extends SQLObjectImpl {
     public SQLOrderBy(){
 
     }
+    
+    public SQLOrderBy(SQLExpr expr) {
+        SQLSelectOrderByItem item = new SQLSelectOrderByItem(expr);
+        item.setParent(this);
+        this.items.add(item);
+    }
 
     public List<SQLSelectOrderByItem> getItems() {
         return this.items;

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

@@ -31,12 +31,19 @@ public class SQLSelectOrderByItem extends SQLObjectImpl {
     public SQLSelectOrderByItem(){
 
     }
+    
+    public SQLSelectOrderByItem(SQLExpr expr){
+        this.setExpr(expr);
+    }
 
     public SQLExpr getExpr() {
         return this.expr;
     }
 
     public void setExpr(SQLExpr expr) {
+        if (expr != null) {
+            expr.setParent(this);
+        }
         this.expr = expr;
     }