Re: [SQL] FUNCTION problem
On Thursday 02 April 2009 6:16:44 pm Adrian Klaver wrote: Now I remember. Its something that trips me up, the RECORD in RETURN setof RECORD is not the same thing as the RECORD in DECLARE RECORD. See below for a better explanation- http://www.postgresql.org/docs/8.3/interactive/plpgsql-declarations.html#PL PGSQL-DECLARATION-RECORDS Note that RECORD is not a true data type, only a placeholder. One should also realize that when a PL/pgSQL function is declared to return type record, this is not quite the same concept as a record variable, even though such a function might use a record variable to hold its result. In both cases the actual row structure is unknown when the function is written, but for a function returning record the actual structure is determined when the calling query is parsed, whereas a record variable can change its row structure on-the-fly. -- Adrian Klaver akla...@comcast.net For this particular case the following works. CREATE OR REPLACE FUNCTION test_function(integer) RETURNS record AS $Body$ DECLARE croid integer; DECLARE R RECORD; BEGIN SELECT INTO croid 2; SELECT INTO R croid,$1; RETURN R; END; $Body$ LANGUAGE plpgsql; -- Adrian Klaver akla...@comcast.net -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
Re: [SQL] FUNCTION problem
On Friday 03 April 2009 6:51:05 am Adrian Klaver wrote: On Thursday 02 April 2009 6:16:44 pm Adrian Klaver wrote: Now I remember. Its something that trips me up, the RECORD in RETURN setof RECORD is not the same thing as the RECORD in DECLARE RECORD. See below for a better explanation- http://www.postgresql.org/docs/8.3/interactive/plpgsql-declarations.html# PL PGSQL-DECLARATION-RECORDS Note that RECORD is not a true data type, only a placeholder. One should also realize that when a PL/pgSQL function is declared to return type record, this is not quite the same concept as a record variable, even though such a function might use a record variable to hold its result. In both cases the actual row structure is unknown when the function is written, but for a function returning record the actual structure is determined when the calling query is parsed, whereas a record variable can change its row structure on-the-fly. -- Adrian Klaver akla...@comcast.net For this particular case the following works. CREATE OR REPLACE FUNCTION test_function(integer) RETURNS record AS $Body$ DECLARE croid integer; DECLARE R RECORD; BEGIN SELECT INTO croid 2; SELECT INTO R croid,$1; RETURN R; END; $Body$ LANGUAGE plpgsql; -- Adrian Klaver akla...@comcast.net Forgot to show how to call it. test=# SELECT * from test_function(1) as test(c1 int,c2 int); c1 | c2 + 2 | 1 (1 row) -- Adrian Klaver akla...@comcast.net -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
Re: [SQL] FUNCTION problem
Adrian Klaver wrote: On Friday 03 April 2009 6:51:05 am Adrian Klaver wrote: On Thursday 02 April 2009 6:16:44 pm Adrian Klaver wrote: Now I remember. Its something that trips me up, the RECORD in RETURN setof RECORD is not the same thing as the RECORD in DECLARE RECORD. See below for a better explanation- http://www.postgresql.org/docs/8.3/interactive/plpgsql-declarations.html# PL PGSQL-DECLARATION-RECORDS Note that RECORD is not a true data type, only a placeholder. One should also realize that when a PL/pgSQL function is declared to return type record, this is not quite the same concept as a record variable, even though such a function might use a record variable to hold its result. In both cases the actual row structure is unknown when the function is written, but for a function returning record the actual structure is determined when the calling query is parsed, whereas a record variable can change its row structure on-the-fly. -- Adrian Klaver akla...@comcast.net For this particular case the following works. CREATE OR REPLACE FUNCTION test_function(integer) RETURNS record AS $Body$ DECLARE croid integer; DECLARE R RECORD; BEGIN SELECT INTO croid 2; SELECT INTO R croid,$1; RETURN R; END; $Body$ LANGUAGE plpgsql; -- Adrian Klaver akla...@comcast.net Forgot to show how to call it. test=# SELECT * from test_function(1) as test(c1 int,c2 int); c1 | c2 + 2 | 1 (1 row) Ah!, I see what you mean about the definition of 'RECORD'. (The lights come on...) And here I thought it would all be so simple. You show a valid, and most informative solution. This should get things working for me. Thank you very much for your help. Peter -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
Re: [SQL] FUNCTION problem
Adrian Klaver wrote: If you are using Postgres 8.1+ then it becomes even easier because you can use OUT parameters in the function argument list to eliminate the as test(c1 int,c2 int) clause. At this point it becomes a A--B--C problem i.e determine what your inputs are, how you want to process them and how you want to return the output. '8.1+'?? Hmmm, I'm using 8.3. I could use that. I got the more complex version of the query to work by backing away from 'plpgsql' as the language and using 'sql' instead. I then nested (terribly ugly) my select statements to generate a single SQL query from all. This allows me to change the output of the query without needing to define a new set of output 'OUT' parameters each time I change things. I have use of the 'OUT' parameters with another set of functions though. Thanks for that. Peter -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
Re: [SQL] FUNCTION problem
- Peter Willis pet...@borstad.com wrote: Adrian Klaver wrote: On Wednesday 01 April 2009 4:31:20 pm Peter Willis wrote: Hello, I am having a problem with a FUNCTION. The function creates just fine with no errors. However, when I call the function postgres produces an error. Perhaps someone can enlighten me. --I can reproduce the error by making a test function --that is much easier to follow that the original: CREATE OR REPLACE FUNCTION test_function(integer) RETURNS SETOF RECORD AS $BODY$ DECLARE croid integer; BEGIN --PERFORM A SMALL CALCULATION --DOESNT SEEM TO MATTER WHAT IT IS SELECT INTO croid 2; --A SELECT STATEMENT OUTPUTS RECORDS (one in this case) SELECT croid,$1; END; $BODY$ LANGUAGE 'plpgsql' VOLATILE --The call looks like the following: SELECT test_function(1); --The resulting error reads as follows: ERROR: query has no destination for result data HINT: If you want to discard the results of a SELECT, use PERFORM instead. CONTEXT: PL/pgSQL function test_function line 5 at SQL statement ** Error ** ERROR: query has no destination for result data SQL state: 42601 Hint: If you want to discard the results of a SELECT, use PERFORM instead. Context: PL/pgSQL function test_function line 5 at SQL statement You have declared function to RETURN SETOF. In order for that to work you need to do RETURN NEXT. See below for difference between RETURN and RETURN NEXT: http://www.postgresql.org/docs/8.3/interactive/plpgsql-control-structures.html#PLPGSQL-CONTROL-STRUCTURES-LOOPS Thank you for the pointer. I tried using FOR/RETURN NEXT as suggested but now get a different error: CREATE OR REPLACE FUNCTION test_function(integer) RETURNS SETOF record AS $BODY$ DECLARE croid integer; DECLARE R RECORD; BEGIN SELECT INTO croid 2; FOR R IN SELECT croid,$1 LOOP RETURN NEXT R; END LOOP; RETURN; END; $BODY$ LANGUAGE 'plpgsql' VOLATILE There is now an error : ERROR: set-valued function called in context that cannot accept a set CONTEXT: PL/pgSQL function test_function line 7 at RETURN NEXT ** Error ** ERROR: set-valued function called in context that cannot accept a set SQL state: 0A000 Context: PL/pgSQL function test_function line 7 at RETURN NEXT PostgreSQL doesn't seem to see 'R' as being a SET OF RECORD Peter Did you happen to catch this: Note that functions using RETURN NEXT or RETURN QUERY must be called as a table source in a FROM clause Try: select * from test_function(1) Adrian Klaver akla...@comcast.net -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
Re: [SQL] FUNCTION problem
Adrian Klaver wrote: Did you happen to catch this: Note that functions using RETURN NEXT or RETURN QUERY must be called as a table source in a FROM clause Try: select * from test_function(1) I did miss that, but using that method to query the function didn't work either. Postgres doesn't see the result as a tabular set of records. Even if I replace the FOR loop with: quote FOR R IN SELECT * FROM pg_database LOOP RETURN NEXT R; END LOOP; /quote I get the same error(s). I don't think postgres likes the unrelated 'SELECT INTO variable [column] FROM [QUERY] LIMIT 1' lines before the FOR loop... I think I need to go back and approach the function from a different direction. Thanks for all the pointers. Peter -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
Re: [SQL] FUNCTION problem
On Thursday 02 April 2009 4:22:06 pm Peter Willis wrote: Adrian Klaver wrote: Did you happen to catch this: Note that functions using RETURN NEXT or RETURN QUERY must be called as a table source in a FROM clause Try: select * from test_function(1) I did miss that, but using that method to query the function didn't work either. Postgres doesn't see the result as a tabular set of records. Even if I replace the FOR loop with: quote FOR R IN SELECT * FROM pg_database LOOP RETURN NEXT R; END LOOP; /quote I get the same error(s). I don't think postgres likes the unrelated 'SELECT INTO variable [column] FROM [QUERY] LIMIT 1' lines before the FOR loop... I think I need to go back and approach the function from a different direction. Thanks for all the pointers. Peter Now I remember. Its something that trips me up, the RECORD in RETURN setof RECORD is not the same thing as the RECORD in DECLARE RECORD. See below for a better explanation- http://www.postgresql.org/docs/8.3/interactive/plpgsql-declarations.html#PLPGSQL-DECLARATION-RECORDS Note that RECORD is not a true data type, only a placeholder. One should also realize that when a PL/pgSQL function is declared to return type record, this is not quite the same concept as a record variable, even though such a function might use a record variable to hold its result. In both cases the actual row structure is unknown when the function is written, but for a function returning record the actual structure is determined when the calling query is parsed, whereas a record variable can change its row structure on-the-fly. -- Adrian Klaver akla...@comcast.net -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
[SQL] FUNCTION problem
Hello, I am having a problem with a FUNCTION. The function creates just fine with no errors. However, when I call the function postgres produces an error. Perhaps someone can enlighten me. --I can reproduce the error by making a test function --that is much easier to follow that the original: CREATE OR REPLACE FUNCTION test_function(integer) RETURNS SETOF RECORD AS $BODY$ DECLARE croid integer; BEGIN --PERFORM A SMALL CALCULATION --DOESNT SEEM TO MATTER WHAT IT IS SELECT INTO croid 2; --A SELECT STATEMENT OUTPUTS RECORDS (one in this case) SELECT croid,$1; END; $BODY$ LANGUAGE 'plpgsql' VOLATILE --The call looks like the following: SELECT test_function(1); --The resulting error reads as follows: ERROR: query has no destination for result data HINT: If you want to discard the results of a SELECT, use PERFORM instead. CONTEXT: PL/pgSQL function test_function line 5 at SQL statement ** Error ** ERROR: query has no destination for result data SQL state: 42601 Hint: If you want to discard the results of a SELECT, use PERFORM instead. Context: PL/pgSQL function test_function line 5 at SQL statement -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
Re: [SQL] FUNCTION problem
On Wednesday 01 April 2009 4:31:20 pm Peter Willis wrote: Hello, I am having a problem with a FUNCTION. The function creates just fine with no errors. However, when I call the function postgres produces an error. Perhaps someone can enlighten me. --I can reproduce the error by making a test function --that is much easier to follow that the original: CREATE OR REPLACE FUNCTION test_function(integer) RETURNS SETOF RECORD AS $BODY$ DECLARE croid integer; BEGIN --PERFORM A SMALL CALCULATION --DOESNT SEEM TO MATTER WHAT IT IS SELECT INTO croid 2; --A SELECT STATEMENT OUTPUTS RECORDS (one in this case) SELECT croid,$1; END; $BODY$ LANGUAGE 'plpgsql' VOLATILE --The call looks like the following: SELECT test_function(1); --The resulting error reads as follows: ERROR: query has no destination for result data HINT: If you want to discard the results of a SELECT, use PERFORM instead. CONTEXT: PL/pgSQL function test_function line 5 at SQL statement ** Error ** ERROR: query has no destination for result data SQL state: 42601 Hint: If you want to discard the results of a SELECT, use PERFORM instead. Context: PL/pgSQL function test_function line 5 at SQL statement You have declared function to RETURN SETOF. In order for that to work you need to do RETURN NEXT. See below for difference between RETURN and RETURN NEXT: http://www.postgresql.org/docs/8.3/interactive/plpgsql-control-structures.html#PLPGSQL-CONTROL-STRUCTURES-LOOPS -- Adrian Klaver akla...@comcast.net -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
[SQL] function problem
Can anybody tell me why the following code when activated by a select only affects the first line of the table??? create or replace function increase(integer) returns void as 'update tab set price=price*(1+$1/100.0)' language sql; Thanks. ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
Re: [SQL] function problem
geraldo [EMAIL PROTECTED] writes: Can anybody tell me why the following code when activated by a select only affects the first line of the table??? create or replace function increase(integer) returns void as 'update tab set price=price*(1+$1/100.0)' language sql; Works fine here. regression=# create table tab (price numeric); CREATE TABLE regression=# insert into tab values(1); INSERT 154584 1 regression=# insert into tab values(10); INSERT 154585 1 regression=# insert into tab values(100); INSERT 154586 1 regression=# select * from tab; price --- 1 10 100 (3 rows) regression=# create or replace function increase(integer) regression-# returns void as 'update tab set price=price*(1+$1/100.0)' regression-# language sql; CREATE FUNCTION regression=# select increase(42); increase -- (1 row) regression=# select * from tab; price -- 1.4200 14.2000 142. (3 rows) regression=# regards, tom lane ---(end of broadcast)--- TIP 9: the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
