diff options
| -rw-r--r-- | mysql-test/r/case.result | 8 | ||||
| -rw-r--r-- | mysql-test/t/case.test | 11 | ||||
| -rw-r--r-- | sql/item_cmpfunc.cc | 19 |
3 files changed, 34 insertions, 4 deletions
diff --git a/mysql-test/r/case.result b/mysql-test/r/case.result index fb0bc19a67e..a5495d0fc3e 100644 --- a/mysql-test/r/case.result +++ b/mysql-test/r/case.result @@ -169,3 +169,11 @@ SELECT CASE '1' WHEN '2' THEN 'BUG' ELSE 'nobug' END; case+union+test case+union+test nobug +create table t1(a float, b int default 3); +insert into t1 (a) values (2), (11), (8); +select min(a), min(case when 1=1 then a else NULL end), +min(case when 1!=1 then NULL else a end) +from t1 where b=3 group by b; +min(a) min(case when 1=1 then a else NULL end) min(case when 1!=1 then NULL else a end) +2 2 2 +drop table t1; diff --git a/mysql-test/t/case.test b/mysql-test/t/case.test index fbbbce15576..fd1b6e5247f 100644 --- a/mysql-test/t/case.test +++ b/mysql-test/t/case.test @@ -119,4 +119,15 @@ SELECT 'case+union+test' UNION SELECT CASE '1' WHEN '2' THEN 'BUG' ELSE 'nobug' END; +# +# Bug #17896: problem with MIN(CASE...) +# + +create table t1(a float, b int default 3); +insert into t1 (a) values (2), (11), (8); +select min(a), min(case when 1=1 then a else NULL end), + min(case when 1!=1 then NULL else a end) +from t1 where b=3 group by b; +drop table t1; + # End of 4.1 tests diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc index f9aa220c181..57a3c9e5623 100644 --- a/sql/item_cmpfunc.cc +++ b/sql/item_cmpfunc.cc @@ -37,10 +37,21 @@ static Item_result item_store_type(Item_result a,Item_result b) static void agg_result_type(Item_result *type, Item **items, uint nitems) { - uint i; - type[0]= items[0]->result_type(); - for (i=1 ; i < nitems ; i++) - type[0]= item_store_type(type[0], items[i]->result_type()); + Item **item, **item_end; + + /* Note: NULL items don't affect the result type */ + *type= STRING_RESULT; + /* Skip beginning NULL items */ + for (item= items, item_end= item + nitems; item < item_end; item++) + if ((*item)->type() != Item::NULL_ITEM) + { + *type= (*item)->result_type(); + item++; + break; + } + for (; item < item_end; item++) + if ((*item)->type() != Item::NULL_ITEM) + *type= item_store_type(type[0], (*item)->result_type()); } static void agg_cmp_type(Item_result *type, Item **items, uint nitems) |