I have a select statement that is generated dynamically based on the supplied parameter. The problem is that postgresql always says:
argument of WHERE must be type boolean, not type character varying no matter what the parameter is. Did I miss anything?
CREATE OR REPLACE FUNCTION getuid(name character varying) RETURNS integer AS $$
DECLARE
statement varchar;
uid integer;
BEGIN
IF ($1 = '') THEN
statement := 'TRUE';
statement := CAST(statement AS BOOLEAN);
ELSE
statement := 'users.keywords ILIKE''' || '%' || $1 || '%''';
END IF;
SELECT INTO uid id FROM users WHERE "statement";
RETURN uid;
END;
$$ LANGUAGE plpgsql
You need EXECUTE if you want to generate dynamic commands inside a function. You could also use two different sections:
CREATE OR REPLACE FUNCTION getuid(name character varying) RETURNS integer AS $$
DECLARE
statement varchar;
uid integer;
BEGIN
IF ($1 = '' OR $1 IS NULL) THEN -- section 1
SELECT id INTO uid FROM users;
ELSE -- section 2
SELECT id INTO uid FROM users WHERE users.keywords ILIKE '%' || $1 || '%';
END IF;
RETURN uid;
END;
$$ LANGUAGE plpgsql;
EXECUTE is a PL/pgSQL statement and not SQL statement. So you have to wrap your dynamic query into PL/pgSQL stored procedure.
Be careful about variable substitution and do not forget to use quote_literal() or quote_nullable() when building up you query.
Have look in documentation here: http://www.postgresql.org/docs/current/static/plpgsql-statements.html#PLPGSQL-STATEMENTS-EXECUTING-DYN
Related
I have a function that takes 3 parameters: huc, id_list, and email.
CREATE OR REPLACE FUNCTION my_app.job_batch(
huc text,
input_list text[],
email text
) RETURNS VOID AS
$$
DECLARE
id text;
BEGIN
FOREACH id IN ARRAY input_list LOOP
EXECUTE 'SELECT * FROM my_app.my_funct(
' || huc || '::text,
' || id || '::text,
' || email || '::text)';
END LOOP;
END;
$$
LANGUAGE plpgsql;
When I try to run the function however, it throws an error: ERROR: column "myhu4" does not exist
SELECT * FROM spg_app.append_spg_job_batch('MYHUC4', array['1021', '1025','1026','1027','0701','0702','0703','0708','0709'], 'myemail#gmail.com');
Why is it referring to myhuc4 as a column and why is displaying it in lower case. Is my syntax below to run the function with those 3 parameters incorrect? Note: If I run the below hardcoded version, it runs fine:
DO $$
DECLARE
id_list text[] := array['1021', '1025','1026','1027','0701','0702','0703','0708','0709'];
id text;
BEGIN
FOREACH id in ARRAY id_list LOOP
EXECUTE 'SELECT * FROM my_app.my_funct(
''MYHU4''::text,
' || id || '::text,
''myemail#gmail.com''::text)'
END LOOP;
END;
$$
LANGUAGE plpgsql;
I suggest to use parameters instead of bad practice of stitching strings, as follows:
CREATE OR REPLACE FUNCTION my_app.job_batch(
huc text,
input_list text[],
email text
) RETURNS VOID AS
$$
DECLARE
id text;
BEGIN
FOREACH id IN ARRAY input_list LOOP
execute format ('SELECT * FROM my_app.my_funct($1, $2, $3)')
using huc, id, email;
END LOOP;
END;
$$
LANGUAGE plpgsql;
as shown in official docs https://www.postgresql.org/docs/current/plpgsql-statements.html#PLPGSQL-STATEMENTS-EXECUTING-DYN
I need to replace schema and table name by parameters in following function (that is currently working perfectly):
CREATE OR REPLACE FUNCTION public.my_function_119()
RETURNS integer
LANGUAGE plpgsql
AS $function$
DECLARE _check INTEGER;
BEGIN
SELECT SUM("length"/1000)
FROM public."National_Grid_multiline"
INTO _check;
RETURN _check;
END
$function$
I have tried following solution (and its numerous variations) :
CREATE OR REPLACE FUNCTION public.my_function_119(schema text, tablename text)
RETURNS INTEGER
LANGUAGE plpgsql
AS
$function$
DECLARE _check INTEGER;
BEGIN
RETURN
'(SELECT SUM((length/1000))::integer FROM ' || schema || '."' || tablename || '")::integer INTO _check' ;
RETURN _check;
END
$function$
but keep running into following error code :
psycopg2.errors.InvalidTextRepresentation: invalid input syntax for type integer: "(SELECT SUM((length/1000))::integer FROM public."National_Grid_multiline")::integer INTO _check"
CONTEXT: PL/pgSQL function my_function_119(text,text) while casting return value to function's return type
Why is this not working ? The 'length' column contains float values.
You have to use dynamic SQL, because you cannot use a parameter for an identifier.
Also, make sure to avoid SQL injection by using format rather than concatenating strings:
EXECUTE
format(
'SELECT SUM((length/1000))::integer FROM %I.%I',
schema,
table_name
)
INTO _check';
You can try this :
CREATE OR REPLACE FUNCTION public.my_function_119(schema text, tablename text)
RETURNS INTEGER
LANGUAGE plpgsql
AS
$function$
DECLARE
res integer ;
BEGIN
EXECUTE E'
(SELECT SUM((length/1000))::integer INTO res FROM ' || schema || '."' || tablename || '"):: integer' ;
RETURN res ;
END ;
$function$
I have a bytea column in a table that contains a function decode(). What I have done to get the actual data is as follows:
select filename, convert_from(data,'UTF-8') from attachments limit 20; //this returns me decode function
select decode(E'...','hex'); // I am executing the above returned function
The above is fine as long as I have to select one row. But now my requirement is to get more than one result. How can I get the result in single query? I have tried using pl/pgsql
CREATE OR REPLACE FUNCTION get_data(integer, _type anyelement, OUT _result anyelement)
AS
$x$
BEGIN
EXECUTE
'SELECT ' || (select convert_from(data,'UTF-8') as data from attachments limit $1)
INTO _result;
END;
$x$
LANGUAGE plpgsql;
But this works only for single row and single column. What I want is a single query to fetch 2 columns without using pl/pgsql if possible. I am using this query from my Java based web app.
Thanks!
You need procedural code for this, since there is no provision for dynamic statements in SQL.
The following function converts all attachments:
CREATE FUNCTION getemall(
IN v_type anyelement,
OUT v_result anyelement
) RETURNS SETOF anyelement
LANGUAGE plpgsql AS
$$DECLARE
v_stmt text;
BEGIN
FOR v_stmt IN
SELECT convert_from(data,'UTF-8')
FROM attachments
LOOP
EXECUTE v_stmt INTO v_result;
RETURN NEXT;
END LOOP;
END;$$;
This is how I have written the function with few changes
CREATE OR REPLACE FUNCTION getmeall(tName text, fNameCol text, dataCol text,fSize
numeric)
RETURNS TABLE(bdata bytea, fname text) LANGUAGE plpgsql AS
$$DECLARE
v_stmt text;
v_name text;
BEGIN
FOR v_stmt,v_name IN
EXECUTE format('SELECT encode(%s, ''escape''), %s FROM %s
WHERE $1 IS NOT NULL AND $2 IS NOT NULL LIMIT $3'
, dataCol, fNameCol, tName)
USING dataCol, fNameCol, fSize
LOOP
fname:=v_name;
IF strpos(v_stmt,'decode') = 1 THEN
EXECUTE 'SELECT ' || v_stmt INTO bdata;
ELSE
bdata:=v_stmt;
END IF;
RETURN NEXT;
END LOOP;
END;$$;
And finally calling it this way.
select * from getmeall('attachments', '"filename"', '"data"',2)
CREATE OR REPLACE FUNCTION demo(vsql text, vals text[])
RETURNS void AS
$BODY$
BEGIN
execute vsql using vals;
END;
$BODY$
LANGUAGE plpgsql VOLATILE;
select demo('select $1 || $2', ARRAY['Barrett', ' Gilmour'] );
ERROR: there is no parameter $2
LINE 1: select $1 || $2
The error is that postgres does not understand that the two items in the array must be spread to the input parameters $1 and $2. It understand the entire array as value for $1
As discussed in SO question https://dba.stackexchange.com/questions/83278/postgressql-dynamic-execute-with-argument-values-in-array, the EXECUTE ... USING will treat an array as a single parameter.
You could try this hack, which edits the passed SQL statement so that $n becomes $1[n]
vsql := regexp_replace( vsql, '[$]([0-9]+)', '$1[\1]', 'g' );
The array vals is treated as a single parameter but the parameterised select can index into it to get the elements.
a_horse_with_no_name mentioned your other problem which is that your function doesn't actually return anything. If you want to see what is being executed:
-- anyelement is a polymorphic pseudo-type
-- problem with returning 'setof record' is that select * from so_demov3() gives error
-- ERROR: a column definition list is required for functions returning "record"
drop function so_demov3(anyelement, text, text[]);
create function so_demov3(rec_type anyelement, p_sql text, p_vals text[]) returns setof anyelement as
$$
declare v_sql text;
begin
-- edit the executable SQL stmt so that $n -> $1[n]
v_sql := regexp_replace( p_sql, '[$]([0-9]+)', '$1[\1]', 'g' );
return query execute v_sql using p_vals;
end;
$$
language plpgsql volatile;
And call it like this:
select * from so_demov3(null::text, 'select $1 || $2', array['Barrett', 'Gilmour'] );
Trying to create a function that looks for sequence with particular name if does not exist should create it. Then returns function value of sequence. Part of function that does not seem to be working is where it tests if sequence already exists. Below is code for function
CREATE OR REPLACE FUNCTION public."tenantSequence"(
vtenantid integer,
vtablename character)
RETURNS bigint AS
$BODY$DECLARE
vSeqName character varying;
vSQL character varying;
BEGIN
select ('t' || trim(to_char(vtenantid,'0000')) || vtablename) INTO vSeqName;
if not exists(SELECT 0 FROM pg_class where relkind = 'S' and relname = vSeqName )
then
vSQL := 'create sequence '||vSeqName||';';
execute vSQL;
ELSE
return 0;
end if;
return nextval(vSeqName) * 10000 + vtenantid;
END$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
ALTER FUNCTION public."tenantSequence"(integer, character)
OWNER TO postgres;
Problem was case as mentioned by a_horse_with_no_name
changed line assign vSeqName to the following
vSeqName := lower('t' || trim(to_char(vtenantid,'0000')) || vtablename);
Now function works as expected.