diff options
| -rw-r--r-- | mysql-test/r/func_concat.result | 7 | ||||
| -rw-r--r-- | mysql-test/t/func_concat.test | 7 | ||||
| -rw-r--r-- | sql/item_strfunc.cc | 5 |
3 files changed, 18 insertions, 1 deletions
diff --git a/mysql-test/r/func_concat.result b/mysql-test/r/func_concat.result index cf6fbf2da4f..94f1f640523 100644 --- a/mysql-test/r/func_concat.result +++ b/mysql-test/r/func_concat.result @@ -64,3 +64,10 @@ select 'a' union select concat('a', -0.0); a a good +select concat((select x from (select 'a' as x) as t1 ), +(select y from (select 'b' as y) as t2 )) from (select 1 union select 2 ) +as t3; +concat((select x from (select 'a' as x) as t1 ), +(select y from (select 'b' as y) as t2 )) +ab +ab diff --git a/mysql-test/t/func_concat.test b/mysql-test/t/func_concat.test index 69ce10c83c9..f546a25f647 100644 --- a/mysql-test/t/func_concat.test +++ b/mysql-test/t/func_concat.test @@ -50,4 +50,11 @@ select 'a' union select concat('a', -0); --replace_result 'a-0.0' good 'a0.0' good select 'a' union select concat('a', -0.0); +# +# Bug#16716: subselect in concat() may lead to a wrong result +# +select concat((select x from (select 'a' as x) as t1 ), + (select y from (select 'b' as y) as t2 )) from (select 1 union select 2 ) + as t3; + # End of 4.1 tests diff --git a/sql/item_strfunc.cc b/sql/item_strfunc.cc index e74d0100b55..0dfbf3b7a1d 100644 --- a/sql/item_strfunc.cc +++ b/sql/item_strfunc.cc @@ -252,11 +252,13 @@ String *Item_func_concat::val_str(String *str) DBUG_ASSERT(fixed == 1); String *res,*res2,*use_as_buff; uint i; + bool is_const= 0; null_value=0; if (!(res=args[0]->val_str(str))) goto null; use_as_buff= &tmp_value; + is_const= args[0]->const_item(); for (i=1 ; i < arg_count ; i++) { if (res->length() == 0) @@ -279,7 +281,7 @@ String *Item_func_concat::val_str(String *str) current_thd->variables.max_allowed_packet); goto null; } - if (res->alloced_length() >= res->length()+res2->length()) + if (!is_const && res->alloced_length() >= res->length()+res2->length()) { // Use old buffer res->append(*res2); } @@ -334,6 +336,7 @@ String *Item_func_concat::val_str(String *str) res= &tmp_value; use_as_buff=str; } + is_const= 0; } } res->set_charset(collation.collation); |