Fixed bug mdev-10660.

The method Item_sum::print did not print opening '(' after the name
of simple window functions (like rank, dense_rank etc).
As a result the view definitions with such window functions
were formed invalid in .frm files.

mysql-test/r/win.result

@@ -456,7 +456,7 @@ pk, c,
 row_number() over (partition by c order by pk
 range between unbounded preceding and current row) as r
 from t1;
-ERROR HY000: Window frame is not allowed with 'row_number('
+ERROR HY000: Window frame is not allowed with 'row_number'
 select
 pk, c,
 rank() over w1 as r
@@ -2463,8 +2463,8 @@ drop table t1;
 #
 # MDEV-11594: window function over implicit grouping
 #
-create table test.t1 (id int);
-insert into test.t1 values (1), (2), (3), (2);
+create table t1 (id int);
+insert into t1 values (1), (2), (3), (2);
 select sum(id) over (order by sum(id)) from t1;
 sum(id) over (order by sum(id))
 1
@@ -2476,8 +2476,8 @@ drop table t1;
 # MDEV-9923: integer constant in order by list 
 #            of window specification
 #
-create table test.t1 (id int);
-insert into test.t1 values (1), (2), (3), (2);
+create table t1 (id int);
+insert into t1 values (1), (2), (3), (2);
 select rank() over (order by 1) from t1;
 rank() over (order by 1)
 1
@@ -2497,3 +2497,27 @@ rank() over (partition by id order by 2)
 1
 1
 drop table t1;
+#
+# MDEV-10660: view using a simple window function 
+#
+create table t1 (id int);
+insert into t1 values (1), (2), (3), (2);
+create view v1(id,rnk) as
+select id, rank() over (order by id) from t1;
+show create view v1;
+View	Create View	character_set_client	collation_connection
+v1	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select `t1`.`id` AS `id`,rank() over ( order by `t1`.`id`) AS `rnk` from `t1`	latin1	latin1_swedish_ci
+select id, rank() over (order by id) from t1;
+id	rank() over (order by id)
+1	1
+2	2
+3	4
+2	2
+select * from v1;
+id	rnk
+1	1
+2	2
+3	4
+2	2
+drop view v1;
+drop table t1;

mysql-test/t/win.test

@@ -1495,8 +1495,8 @@ drop table t1;
 --echo # MDEV-11594: window function over implicit grouping
 --echo #
 
-create table test.t1 (id int);
-insert into test.t1 values (1), (2), (3), (2);
+create table t1 (id int);
+insert into t1 values (1), (2), (3), (2);
 
 select sum(id) over (order by sum(id)) from t1;
 
@@ -1509,11 +1509,29 @@ drop table t1;
 --echo #            of window specification
 --echo #
 
-create table test.t1 (id int);
-insert into test.t1 values (1), (2), (3), (2);
+create table t1 (id int);
+insert into t1 values (1), (2), (3), (2);
 
 select rank() over (order by 1) from t1;
 select rank() over (order by 2) from t1;
 select rank() over (partition by id order by 2) from t1;
 
 drop table t1;
+
+--echo #
+--echo # MDEV-10660: view using a simple window function 
+--echo #
+
+create table t1 (id int);
+insert into t1 values (1), (2), (3), (2);
+
+create view v1(id,rnk) as
+  select id, rank() over (order by id) from t1;
+
+show create view v1;
+
+select id, rank() over (order by id) from t1;
+select * from v1;
+
+drop view v1;
+drop table t1;

sql/item_sum.cc

@@ -471,6 +471,13 @@ void Item_sum::print(String *str, enum_query_type query_type)
   /* orig_args is not filled with valid values until fix_fields() */
   Item **pargs= fixed ? orig_args : args;
   str->append(func_name());
+  /*
+    TODO:
+    The fact that func_name() may return a name with an extra '('
+    is really annoying. This shoud be fixed.
+  */
+  if (!is_aggr_sum_func())
+    str->append('(');
   for (uint i=0 ; i < arg_count ; i++)
   {
     if (i)
@@ -594,7 +601,9 @@ Item *Item_sum::result_item(THD *thd, Field *field)
 
 bool Item_sum::check_vcol_func_processor(void *arg)
 {
-  return mark_unsupported_function(func_name(), ")", arg, VCOL_IMPOSSIBLE);
+  return mark_unsupported_function(func_name(), 
+                                   is_aggr_sum_func() ? ")" : "()",
+                                   arg, VCOL_IMPOSSIBLE);
 }
 
 

sql/item_sum.h

@@ -409,10 +409,31 @@ class Item_sum :public Item_func_or_sum
   Item_sum(THD *thd, Item_sum *item);
   enum Type type() const { return SUM_FUNC_ITEM; }
   virtual enum Sumfunctype sum_func () const=0;
+  bool is_aggr_sum_func()
+  {
+    switch (sum_func()) {
+    case COUNT_FUNC:
+    case COUNT_DISTINCT_FUNC:
+    case SUM_FUNC:
+    case SUM_DISTINCT_FUNC:
+    case AVG_FUNC:
+    case AVG_DISTINCT_FUNC:
+    case MIN_FUNC:
+    case MAX_FUNC:
+    case STD_FUNC:
+    case VARIANCE_FUNC:
+    case SUM_BIT_FUNC:
+    case UDF_SUM_FUNC:
+    case GROUP_CONCAT_FUNC:
+      return true;
+    default:
+      return false;
+    }
+  }
   /**
     Resets the aggregate value to its default and aggregates the current
     value of its attribute(s).
-  */  
+  */
   inline bool reset_and_add() 
   { 
     aggregator_clear();

sql/item_windowfunc.h

@@ -127,7 +127,7 @@ class Item_sum_row_number: public Item_sum_int
   }
   const char*func_name() const
   {
-    return "row_number(";
+    return "row_number";
   }
 
   Item *get_copy(THD *thd, MEM_ROOT *mem_root)