Thread: in PlPgSQL function, how to use variable in a "select ... into .. where " query
Hello,
In pl/pgsql (postgresql 8.01), how to use variables in select .. into ..
command
CREATE OR REPLACE FUNCTION test(VARCHAR) RETURNS VARCHAR AS $$
DECLARE var1 ALIAS FOR $1; cm_tableName
tableA.col1%TYPE; T1 VARCHAR := 'sourceTable'; query_value VARCHAR ;
BEGIN
SELECT col2 INTO cm_tableName FROM T1 WHERE col1 = var1 ; EXECUTE query_value;
RETURN cm_tableName;END;
$$ language 'plpgsql' IMMUTABLE STRICT;
select test('abc');
Failed.
Also, tried "SELECT col2 INTO cm_tableName FROM || T1 WHERE col1 = ||
var1 " and
"SELECT col2 INTO cm_tableName FROM || T1 || WHERE col1 = || var1"
Failed as well.
T1 and var1 both are variables, may I how to use variables in a "select
... into " query please?
Thanks a lot,
Ying
Does not work either, the whole function is:
create table t1(col1 varchar(3), col2 varchar(100));
insert into t1 values('001', 'Result 1');
insert into t1 values('002', 'Result 2');
insert into t1 values('003', 'Result 3');
CREATE OR REPLACE FUNCTION test(VARCHAR) RETURNS VARCHAR AS $$
DECLARE col1_value ALIAS FOR $1; cm_tableName
st1_legend.code_map_tablename%TYPE; lengendTableName VARCHAR := 't1'; query_value VARCHAR ;
BEGIN
SELECT INTO cm_tableName col2 FROM lengendTableName WHERE col1 =
col1_value ; EXECUTE query_value; RETURN cm_tableName;END;
$$ language 'plpgsql' IMMUTABLE STRICT;
select test('001');
Error:
ERROR: syntax error at or near "$1" at character 20
QUERY: SELECT col2 FROM $1 WHERE col1 = $2
CONTEXT: PL/pgSQL function "test" line 8 at select into variables
LINE 1: SELECT col2 FROM $1 WHERE col1 = $2
Does it mean I have to use the cursor ?
Thanks,
Ying
>I think it is SELECT INTO cm_tableName col2 FROM ... WHERE ...
>
>2006/3/17, Emi Lu <emilu@encs.concordia.ca>:
>
>
>>Hello,
>>
>>In pl/pgsql (postgresql 8.01), how to use variables in select .. into ..
>>command
>>
>>CREATE OR REPLACE FUNCTION test(VARCHAR) RETURNS VARCHAR AS $$
>>DECLARE
>> var1 ALIAS FOR $1;
>> cm_tableName tableA.col1%TYPE;
>> T1 VARCHAR := 'sourceTable';
>> query_value VARCHAR ;
>>BEGIN
>>
>> SELECT col2 INTO cm_tableName FROM T1 WHERE col1 = var1 ;
>> EXECUTE query_value;
>>
>>
>> RETURN cm_tableName;
>> END;
>>$$ language 'plpgsql' IMMUTABLE STRICT;
>>
>>select test('abc');
>>
>>Failed.
>>
>>
>>Also, tried "SELECT col2 INTO cm_tableName FROM || T1 WHERE col1 = ||
>>var1 " and
>>"SELECT col2 INTO cm_tableName FROM || T1 || WHERE col1 = || var1"
>>
>>Failed as well.
>>
>>T1 and var1 both are variables, may I how to use variables in a "select
>>... into " query please?
>>
>>Thanks a lot,
>>Ying
>>
>>
>>
>>
>>
>>---------------------------(end of broadcast)---------------------------
>>TIP 6: explain analyze is your friend
>>
>>
>>
am 17.03.2006, um 14:23:57 -0500 mailte Emi Lu folgendes:
> Does not work either, the whole function is:
>
> create table t1(col1 varchar(3), col2 varchar(100));
> insert into t1 values('001', 'Result 1');
> insert into t1 values('002', 'Result 2');
> insert into t1 values('003', 'Result 3');
>
> CREATE OR REPLACE FUNCTION test(VARCHAR) RETURNS VARCHAR AS $$
> DECLARE
> col1_value ALIAS FOR $1;
> cm_tableName st1_legend.code_map_tablename%TYPE;
> lengendTableName VARCHAR := 't1';
> query_value VARCHAR ;
> BEGIN
>
> SELECT INTO cm_tableName col2 FROM lengendTableName WHERE col1 =
> col1_value ;
This can't work, read the docu:
http://www.postgresql.org/docs/8.1/interactive/plpgsql-statements.html#PLPGSQL-STATEMENTS-EXECUTING-DYN
You should build a string with your SQL and EXECUTE this string.
HTH, Andreas
--
Andreas Kretschmer (Kontakt: siehe Header)
Heynitz: 035242/47215, D1: 0160/7141639
GnuPG-ID 0x3FFF606C http://wwwkeys.de.pgp.net=== Schollglas Unternehmensgruppe ===
>>Does not work either, the whole function is:
>>
>>create table t1(col1 varchar(3), col2 varchar(100));
>>insert into t1 values('001', 'Result 1');
>>insert into t1 values('002', 'Result 2');
>>insert into t1 values('003', 'Result 3');
>>
>>CREATE OR REPLACE FUNCTION test(VARCHAR) RETURNS VARCHAR AS $$
>>DECLARE
>> col1_value ALIAS FOR $1;
>>cm_tableName st1_legend.code_map_tablename%TYPE;
>>lengendTableName VARCHAR := 't1';
>> query_value VARCHAR ;
>>BEGIN
>>
>> SELECT INTO cm_tableName col2 FROM lengendTableName WHERE col1 =
>>col1_value ;
>>
>>
>
>This can't work, read the docu:
>http://www.postgresql.org/docs/8.1/interactive/plpgsql-statements.html#PLPGSQL-STATEMENTS-EXECUTING-DYN
>
>You should build a string with your SQL and EXECUTE this string.
>
>
Thank you Andreas. Unfortunately it did not work. maybe I made something
wrong?
drop table t1;
create table t1(col1 varchar(3), col2 varchar(100));
insert into t1 values('001', 'Result 1');
insert into t1 values('002', 'Result 2');
insert into t1 values('003', 'Result 3');
CREATE OR REPLACE FUNCTION test(VARCHAR) RETURNS VARCHAR AS $$
DECLARE col1_value ALIAS FOR $1; cm_tableName
st1_legend.code_map_tablename%TYPE; lengendTableName VARCHAR := 't1'; query_value VARCHAR ;
BEGIN query_value := 'SELECT col2 FROM lengendTableName WHERE col1 = \'' ||
col1_value || '\''; EXECUTE query_value INTO cm_tableName;
RETURN cm_tableName;
END;
$$ language 'plpgsql' IMMUTABLE STRICT;
select test('001');
Error:
ERROR: syntax error at or near "$2" at character 20
QUERY: SELECT $1 INTO $2
CONTEXT: PL/pgSQL function "test" line 9 at execute statement
LINE 1: SELECT $1 INTO $2
I am using postgresql 8.0.1, and I am afraid that 8.0 does not support
"excecute ... into ...."
http://www.postgresql.org/docs/8.0/static/plpgsql-statements.html
I will try to use cursor.
Thank you very much for all your help anyway.
Ying
On Friday 17 March 2006 15:33, Emi Lu wrote:
> >>Does not work either, the whole function is:
> >>
> >>create table t1(col1 varchar(3), col2 varchar(100));
> >>insert into t1 values('001', 'Result 1');
> >>insert into t1 values('002', 'Result 2');
> >>insert into t1 values('003', 'Result 3');
> >>
> >>CREATE OR REPLACE FUNCTION test(VARCHAR) RETURNS VARCHAR AS $$
> >>DECLARE
> >> col1_value ALIAS FOR $1;
> >>cm_tableName st1_legend.code_map_tablename%TYPE;
> >>lengendTableName VARCHAR := 't1';
> >> query_value VARCHAR ;
> >>BEGIN
> >>
> >> SELECT INTO cm_tableName col2 FROM lengendTableName WHERE col1 =
> >>col1_value ;
> >
> >This can't work, read the docu:
> >http://www.postgresql.org/docs/8.1/interactive/plpgsql-statements.html#PLP
> >GSQL-STATEMENTS-EXECUTING-DYN
> >
> >You should build a string with your SQL and EXECUTE this string.
>
> Thank you Andreas. Unfortunately it did not work. maybe I made something
> wrong?
>
> drop table t1;
> create table t1(col1 varchar(3), col2 varchar(100));
> insert into t1 values('001', 'Result 1');
> insert into t1 values('002', 'Result 2');
> insert into t1 values('003', 'Result 3');
>
> CREATE OR REPLACE FUNCTION test(VARCHAR) RETURNS VARCHAR AS $$
> DECLARE
> col1_value ALIAS FOR $1;
> cm_tableName st1_legend.code_map_tablename%TYPE;
> lengendTableName VARCHAR := 't1';
> query_value VARCHAR ;
> BEGIN
> query_value := 'SELECT col2 FROM lengendTableName WHERE col1 = \'' ||
> col1_value || '\'';
>
> EXECUTE query_value INTO cm_tableName;
>
> RETURN cm_tableName;
> END;
> $$ language 'plpgsql' IMMUTABLE STRICT;
> select test('001');
>
This function would work on 8.1, provided you created the sql statement
correctly:
query_value := 'SELECT col2 FROM ' ||lengendTableName||' WHERE col1 = \'' ||
col1_value || '\'';
>
> I am using postgresql 8.0.1, and I am afraid that 8.0 does not support
> "excecute ... into ...."
>
In which case you could use:
FOR cm_tableName IN EXECUTE query_value LOOPRETURN cm_tableNameEND LOOP
which is a little hacky, though you could use a second variable for assignment
if you felt strongly about it.
--
Robert Treat
Build A Brighter Lamp :: Linux Apache {middleware} PostgreSQL