hi 2017-03-09 17:19 GMT+01:00 Pavel Stehule <pavel.steh...@gmail.com>:
> > > 2017-03-09 13:18 GMT+01:00 Surafel Temesgen <surafel3...@gmail.com>: > >> Hi , >> >> Here is a patch corrected as your feedback except missed tests case >> because corresponding by clause is implemented on the top of set operation >> and you can’t do that to set operation without corresponding by clause too >> > > I don't understand. > > The following statement should to work > > postgres=# select 10 as a, 20 as b union corresponding select 20 as a, 30 > as b, 40 as c; > > ERROR: each UNION query must have the same number of columns > LINE 1: ...elect 10 as a, 20 as b union corresponding select 20 as a, 3... > > > Corresponding clause should to work like projection filter. > I found a link to postgresql mailing list related to some older try to this feature implementation https://www.postgresql.org/message-id/cajzswkx7c6wmfo9py4baf8vhz_ofko3afsosjpsb17rgmgb...@mail.gmail.com > Regards > > Pavel > > >> >> Eg >> >> >> postgres=# SELECT 1 a, 2 b, 3 c UNION SELECT 4 a, 5 b, 6 c, 8 d; >> >> ERROR: each UNION query must have the same number of columns >> >> LINE 1: SELECT 1 a, 2 b, 3 c UNION SELECT 4 a, 5 b, 6 c, 8 d; >> >> ^ >> >> postgres=# create table t1(a int, b int, c int); >> >> CREATE TABLE >> >> postgres=# create table t2(a int, b int); >> >> CREATE TABLE >> >> >> >> postgres=# select * from t1 union select * from t2; >> >> ERROR: each UNION query must have the same number of columns >> >> LINE 1: select * from t1 union select * from t2; >> >> >> >> Thanks >> >> Surafel >> >> On Tue, Mar 7, 2017 at 10:26 PM, Pavel Stehule <pavel.steh...@gmail.com> >> wrote: >> >>> Hi >>> >>> I am sending a review of this interesting feature. >>> >>> I found following issues, questions: >>> >>> 1. unclosed tags <optional> in documentation >>> 2. bad name "changeTargetEntry" - should be makeTargetEntry? >>> 3. Why you removed lot of asserts in prepunion.c? These asserts should >>> be valid still >>> 4. make_coresponding_target has wrong formatting >>> 5. error "%s queries with a CORRESPONDING clause must have at least one >>> column with the same name" has wrong formatting, you can show position >>> 6. previous issue is repeated - look on formatting ereport function, >>> please, you can use DETAIL and HINT fields >>> 7. corresponding clause should to contain column list (I am looking to >>> ANSI/SQL 99) - you are using expr_list, what has not sense and probably it >>> has impact on all implementation. >>> 8. typo orderCorrespondingLsit(List *targetlist) >>> 9. I miss more tests for CORRESPONDING BY >>> 10. if I understand to this feature, this query should to work >>> >>> postgres=# SELECT 1 a, 2 b, 3 c UNION CORRESPONDING BY (c,b) SELECT 4 a, 5 >>> b, 6 c, 8 d; >>> ERROR: each UNION query must have the same number of columns >>> LINE 1: ...1 a, 2 b, 3 c UNION CORRESPONDING BY (c,b) SELECT 4 a, 5 b, ... >>> >>> postgres=# create table t1(a int, b int, c int); >>> CREATE TABLE >>> Time: 63,260 ms >>> postgres=# create table t2(a int, b int); >>> CREATE TABLE >>> Time: 57,120 ms >>> postgres=# select * from t1 union corresponding select * from t2; >>> ERROR: each UNION query must have the same number of columns >>> LINE 1: select * from t1 union corresponding select * from t2; >>> >>> If it is your first patch to Postgres, then it is perfect work! >>> >>> The @7 is probably most significant - I dislike a expression list there. >>> name_list should be better there. >>> >>> Regards >>> >>> Pavel >>> >>> >> >
