Fix for BUG#13419: In "ref" optimizer, take into account that item=Item_func_in(x,y) is

not equivalent to "x=y" when item->negated == TRUE.

mysql-test/r/func_in.result

@@ -193,3 +193,12 @@ select * from t1 where a in (NULL, 'aa');
 a
 aa
 drop table t1;
+create table t1 (id int, key(id));
+insert into t1 values (1),(2),(3);
+select count(*) from t1 where id not in (1);
+count(*)
+2
+select count(*) from t1 where id not in (1,2);
+count(*)
+1
+drop table t1;

mysql-test/t/func_in.test

@@ -102,4 +102,11 @@ insert into t1 values ('aa'), ('bb');
 select * from t1 where a in (NULL, 'aa');
 drop table t1;
 
+# BUG#13419
+create table t1 (id int, key(id));
+insert into t1 values (1),(2),(3);
+select count(*) from t1 where id not in (1);
+select count(*) from t1 where id not in (1,2);
+drop table t1;
+
 # End of 4.1 tests

sql/sql_select.cc

@@ -2140,7 +2140,6 @@ merge_key_fields(KEY_FIELD *start,KEY_FIELD *new_fields,KEY_FIELD *end,
     field			Field used in comparision
     eq_func			True if we used =, <=> or IS NULL
     value			Value used for comparison with field
-                                Is NULL for BETWEEN and IN
     usable_tables		Tables which can be used for key optimization
 
   NOTES
@@ -2325,7 +2324,8 @@ add_key_fields(KEY_FIELD **key_fields,uint *and_level,
       add_key_field(key_fields,*and_level,cond_func,
 		    ((Item_field*)(cond_func->key_item()->real_item()))->field,
                     cond_func->argument_count() == 2 &&
-                    cond_func->functype() == Item_func::IN_FUNC,
+                    cond_func->functype() == Item_func::IN_FUNC &&
+                    !((Item_func_in*)cond_func)->negated,
                     cond_func->arguments()+1, cond_func->argument_count()-1,
                     usable_tables);
     break;