[Internal] Query: Adds Support for ORDER BY RANK in SQL DOM

Microsoft.Azure.Cosmos/src/Query/Core/Parser/CstToAstVisitor.cs

@@ -355,15 +355,27 @@ public override SqlObject VisitGroup_by_clause([NotNull] sqlParser.Group_by_clau
         public override SqlObject VisitOrder_by_clause([NotNull] sqlParser.Order_by_clauseContext context)
         {
             Contract.Requires(context != null);
-
-            List<SqlOrderByItem> orderByItems = new List<SqlOrderByItem>();
-            foreach (sqlParser.Order_by_itemContext orderByItemContext in context.order_by_items().order_by_item())
-            {
-                SqlOrderByItem orderByItem = (SqlOrderByItem)this.VisitOrder_by_item(orderByItemContext);
-                orderByItems.Add(orderByItem);
-            }
-
-            return SqlOrderByClause.Create(orderByItems.ToImmutableArray());
+
+            bool rank = context.K_RANK() != null;
+            List<SqlOrderByItem> orderByItems = new List<SqlOrderByItem>();
+            if (rank)
+            {
+                foreach (sqlParser.Score_expression_order_by_itemContext scoreOrderByItemContext in context.score_expression_order_by_items().score_expression_order_by_item())
+                {
+                    SqlOrderByItem orderByItem = (SqlOrderByItem)this.VisitScore_expression_order_by_item(scoreOrderByItemContext);
+                    orderByItems.Add(orderByItem);
+                }
+            }
+            else
+            {
+                foreach (sqlParser.Order_by_itemContext orderByItemContext in context.order_by_items().order_by_item())
+                {
+                    SqlOrderByItem orderByItem = (SqlOrderByItem)this.VisitOrder_by_item(orderByItemContext);
+                    orderByItems.Add(orderByItem);
+                }
+            }
+
+            return SqlOrderByClause.Create(rank, orderByItems.ToImmutableArray());
         }
 
         public override SqlObject VisitOrder_by_item([NotNull] sqlParser.Order_by_itemContext context)
@@ -388,6 +400,31 @@ public override SqlObject VisitOrder_by_item([NotNull] sqlParser.Order_by_itemCo
                 }
             }
 
+            return SqlOrderByItem.Create(expression, isDescending);
+        }
+
+        public override SqlObject VisitScore_expression_order_by_item([NotNull] sqlParser.Score_expression_order_by_itemContext context)
+        {
+            Contract.Requires(context != null);
+
+            SqlFunctionCallScalarExpression expression = (SqlFunctionCallScalarExpression)this.Visit(context.function_call_scalar_expression());
+            bool? isDescending = null;
+            if (context.sort_order() != null)
+            {
+                if (context.sort_order().K_ASC() != null)
+                {
+                    isDescending = false;
+                }
+                else if (context.sort_order().K_DESC() != null)
+                {
+                    isDescending = true;
+                }
+                else
+                {
+                    throw new ArgumentOutOfRangeException($"Unknown sort order : {context.sort_order()}.");
+                }
+            }
+
             return SqlOrderByItem.Create(expression, isDescending);
         }
 

Microsoft.Azure.Cosmos/src/Query/Core/Parser/sql.g4

@@ -58,9 +58,17 @@ group_by_clause : K_GROUP K_BY scalar_expression_list ;
 /*--------------------------------------------------------------------------------*/
 /* ORDER BY */
 /*--------------------------------------------------------------------------------*/
-order_by_clause : K_ORDER K_BY order_by_items ;
+order_by_clause 
+    : K_ORDER K_BY order_by_items 
+    | K_ORDER K_BY K_RANK score_expression_order_by_items
+    ;
+
+score_expression_order_by_items : score_expression_order_by_item (',' score_expression_order_by_item)* ;
+score_expression_order_by_item : function_call_scalar_expression sort_order? ;
+
 order_by_items : order_by_item (',' order_by_item)* ;
 order_by_item : scalar_expression sort_order? ;
+
 sort_order
     : K_ASC
     | K_DESC
@@ -227,6 +235,7 @@ K_NULL : 'null';
 K_OFFSET : O F F S E T;
 K_OR : O R;
 K_ORDER : O R D E R;
+K_RANK : R A N K;
 K_RIGHT : R I G H T;
 K_SELECT : S E L E C T;
 K_TOP : T O P;