MDEV-34278: Implements DISTINCT for ST_Collect

Implements the DISTINCT modifier for ST_Collect Author: StefanoPetrilli <stefanop_1999@hotmail.it>

Author: StefanoPetrilli

mysql-test/main/spatial_utility_function_collect.result

@@ -18,6 +18,13 @@ ST_EQUALS( (SELECT ST_COLLECT( location ) AS t FROM
 table_simple_aggregation) , ST_GEOMFROMTEXT('MULTIPOINT(0 0,0 0,1 0,2
 0,3 0) ',4326))
 1
+SELECT ST_EQUALS( (SELECT ST_COLLECT( DISTINCT location ) AS t FROM
+table_simple_aggregation) , ST_GEOMFROMTEXT('MULTIPOINT(0 0,1 0,2 0,3
+0) ',4326));
+ST_EQUALS( (SELECT ST_COLLECT( DISTINCT location ) AS t FROM
+table_simple_aggregation) , ST_GEOMFROMTEXT('MULTIPOINT(0 0,1 0,2 0,3
+0) ',4326))
+1
 INSERT INTO table_simple_aggregation (location) VALUES
 ( ST_GEOMFROMTEXT('POINT(0 -0)' ,4326)),
 ( NULL);

mysql-test/main/spatial_utility_function_collect.test

@@ -35,9 +35,9 @@ table_simple_aggregation) , ST_GEOMFROMTEXT('MULTIPOINT(0 0,0 0,1 0,2
 0,3 0) ',4326));
 # --echo # Functional requirement F-8 Shall support DISTINCT in aggregates
 # --echo # result shall be 1
-# SELECT ST_EQUALS( (SELECT ST_COLLECT( DISTINCT location ) AS t FROM
-# table_simple_aggregation) , ST_GEOMFROMTEXT('MULTIPOINT(0 0,1 0,2 0,3
-# 0) ',4326));
+SELECT ST_EQUALS( (SELECT ST_COLLECT( DISTINCT location ) AS t FROM
+table_simple_aggregation) , ST_GEOMFROMTEXT('MULTIPOINT(0 0,1 0,2 0,3
+0) ',4326));
 # --echo # Functional requirement F-5: ST_COLLECT shall support group by, which
 # --echo # is given by aggregation machinery
 # --echo # result shall be

sql/item_sum.cc

@@ -4621,6 +4621,9 @@ bool Item_func_collect::add() {
  if (tmp_arg[0]->null_value)
  return 0;
 
+ if(is_distinct && list_contains_element(wkb))
+ return 0;
+
  current_geometry_srid= uint4korr(wkb->ptr());
  if (geometries.is_empty())
  srid= current_geometry_srid;
@@ -4636,7 +4639,6 @@ bool Item_func_collect::add() {
 
 
 void Item_func_collect::remove() {
- String value;
  String *wkb= args[0]->val_str(&value);
  has_cached_result= false;
 
@@ -4661,17 +4663,34 @@ void Item_func_collect::remove() {
 }
 
 
-Item_func_collect::Item_func_collect(THD *thd, Item *item_par) :
+bool Item_func_collect::list_contains_element(String *wkb) {
+ List_iterator<String> geometries_iterator(geometries);
+ String* temp_geometry;
+ while ((temp_geometry= geometries_iterator++))
+ {
+ String temp(temp_geometry->ptr(), temp_geometry->length(), &my_charset_bin);
+
+ if (wkb->eq(&temp, &my_charset_bin))
+ return true;
+ }
+
+ return false;
+}
+
+
+Item_func_collect::Item_func_collect(THD *thd, bool is_distinct, Item *item_par) :
  Item_sum_int(thd, item_par),
  mem_root(thd->mem_root),
+ is_distinct(is_distinct),
  group_collect_max_len(thd->variables.group_concat_max_len)
 {
 }
 
 
-Item_func_collect::Item_func_collect(THD *thd, Item_func_collect *item) :
+Item_func_collect::Item_func_collect(THD *thd, bool is_distinct, Item_func_collect *item) :
  Item_sum_int(thd, item),
  mem_root(thd->mem_root),
+ is_distinct(is_distinct),
  group_collect_max_len(thd->variables.group_concat_max_len)
 {
 }
@@ -4748,5 +4767,5 @@ String *Item_func_collect::val_str(String *str)
 
 
 Item *Item_func_collect::copy_or_same(THD *thd) {
- return new (thd->mem_root) Item_func_collect(thd, this);
+ return new (thd->mem_root) Item_func_collect(thd, is_distinct, this);
 }

sql/item_sum.h

@@ -2125,6 +2125,7 @@ class Item_func_collect :public Item_sum_int
  bool has_cached_result;
  String cached_result;
  MEM_ROOT *mem_root;
+ bool is_distinct;
  List<String> geometries;
  String value;
  const uint group_collect_max_len;
@@ -2133,10 +2134,11 @@ class Item_func_collect :public Item_sum_int
  bool add() override;
  void cleanup() override;
  void remove() override;
+ bool list_contains_element(String* wkb);
 
 public:
- Item_func_collect(THD *thd, Item *item_par);
- Item_func_collect(THD *thd, Item_func_collect *item);
+ Item_func_collect(THD *thd, bool is_distinct, Item *item_par);
+ Item_func_collect(THD *thd, bool is_distinct, Item_func_collect *item);
 
  enum Sumfunctype sum_func () const override
  {

sql/sql_yacc.yy

@@ -11311,9 +11311,9 @@ sum_expr:
  if (unlikely($$ == NULL))
  MYSQL_YYABORT;
  }
- | ST_COLLECT_SYM '(' in_sum_expr ')'
+ | ST_COLLECT_SYM '(' opt_distinct in_sum_expr ')'
  {
- $$= new (thd->mem_root) Item_func_collect(thd, $3);
+ $$= new (thd->mem_root) Item_func_collect(thd, $3, $4);
  if (unlikely($$ == NULL))
  MYSQL_YYABORT;
  }