I am new to creating functions in postgresql. The version that I'm using is rather old. It's 8.2.15 (not my choice, but my org's). The following example is trying to apply one function to a temp table in another function.
-- First function
create or replace function inner_func(_tbl anyelement)
RETURNS void AS
$$
BEGIN
EXECUTE 'ALTER TABLE ' || _tbl || ' ADD COLUMN d_amount INTEGER';
EXECUTE 'UPDATE ' || _tbl || ' SET d_amount = 2* amount';
RETURN;
END;
$$
LANGUAGE plpgsql volatile;
-- Second function
CREATE OR REPLACE FUNCTION outer_func()
RETURNS void AS
$$
BEGIN
DROP TABLE IF EXISTS my_temp;
CREATE TEMP TABLE my_temp
(id serial primary key,
amount integer
);
INSERT into my_temp (amount) values (10),(20);
-- now apply the inner_func right here
EXECUTE 'SELECT inner_func(' || quote_ident('my_temp') || ')';
RETURN;
END;
LANGUAGE plpgsql volatile;
When I run
SELECT outer_func();
It spits out an ERROR:
column "my_temp" does not exist
But the inner_func works if I use it on its own like the following:
create temp table my_temp2
(id serial primary key,
amount integer
);
INSERT INTO my_temp2 (amount) values (10),(20);
SELECT inner_func(quote_ident('my_temp2'));
SELECT * from my_temp2;
id amount d_amount
1 10 20
2 20 40
How can I make this inner_func work inside outer_func? Any idea?
It looks like the problem is here:
EXECUTE 'SELECT inner_func(' || quote_ident('my_temp') || ')';
=>
EXECUTE 'SELECT inner_func(quote_ident(' || quote_literal('my_temp') || '));';
DBFiddle Demo
Related
I am a newbie wrt functions and I am struggling with using the name of a table in the function body. I get an error "SQL Error [42703]: ERROR: column "tname" does not exist" when I call the function using
select "JsonToView"('data_import.import_360xero_report');
My code is below
create or replace
function data_import."JsonToView"(tname text) returns numeric
language plpgsql
as $function$
begin
do
$$
declare
l_keys text;
begin
drop view if exists v_json_view cascade;
select
string_agg(distinct format('import_data ->> %L as %I', jkey, jkey), ', ')
into
l_keys
from
import_360xero_report,
json_object_keys(import_data) as t(jkey);
execute 'create view v_json_view as select ' || l_keys || ' from ' || tname;
end;
$$;
return 0;
end $function$ ;
I have modified the code and the second create view query works with the table name but the first one does not.
Below if my modified code
create or replace
function data_import."JsonToView"(tname text) returns numeric
language plpgsql
as $function$
declare
l_keys text;
begin
drop view if exists v_json_view cascade;
execute $a$select
string_agg(distinct format('import_data ->> %L as %I', jkey, jkey), ', ')
into
l_keys
from $a$ ||
tname || $b$,
json_object_keys(import_data) as t(jkey)$b$;
execute 'create view v_json_view as select ' || l_keys || ' from ' || tname;
return 0;
end $function$ ;
The error I am getting is
SQL Error [0A000]: ERROR: EXECUTE of SELECT ... INTO is not implemented
Hint: You might want to use EXECUTE ... INTO or EXECUTE CREATE TABLE ... AS instead.
Where: PL/pgSQL function "JsonToView"(text) line 10 at EXECUTE
The problem is the superfluous nested DO statement.
The variable tname exists only in the scope of the function, not in the nested DO statement. DO is an SQL statement, not a PL/pgSQL statement, and there are no variables in SQL. Also, DO does not allow parameters.
Get rid of the DO and you will be fine.
I have a two tables, table_version_1 and table_version_2, I am trying to generate a new table based on these two tables. For which I have to write 4 stored procedures,
procedure1, procedure2, procedure3, procedure4
I am triggering procedure1 from my application
select * from procedure1
I am calling procedure2 in procedure1
PERFORM procedure2
and I am calling procedure3 in procedure2
PERFORM procedure3
and calling procedure4 in procedure3
PERFORM procedure3
My stored procedure looks something like below.
CREATE OR REPLACE FUNCTION procedure1(tb_name, compare_tb_name, file_version, compare_file_version)
RETURNS text
LANGUAGE 'plpgsql'
COST 100
VOLATILE
AS $BODY$
DECLARE
createquery text;
fpo_data jsonb;
inddata jsonb;
f_primary_key text;
rowscount INTEGER;
datacount INTEGER;
fcdata1 text;
fid INTEGER;
BEGIN
createquery := 'CREATE TABLE IF NOT EXISTS ' || tb_name || '_' || file_version || '_' || compare_file_version || '_pk(
id serial PRIMARY KEY,
fc_pkey1 VARCHAR (250) NULL,
fc_pkey2 VARCHAR (250) NULL,
fc_pkey3 VARCHAR (250) NULL,
fpo_data TEXT NULL,
fid INTEGER NULL
)';
EXECUTE createquery;
EXECUTE 'SELECT count(*) FROM ' || tb_name || '_' || file_version || '_' || compare_file_version || '_pk' INTO rowscount;
EXECUTE 'SELECT count(*) FROM ' || tb_name INTO datacount;
IF(rowscount <> datacount) THEN
EXECUTE 'SELECT json_agg((fpdata, foseqid))::jsonb
FROM (SELECT fo_data AS fpdata, fo_seq_id as foseqid
FROM '||tb_name||'
LIMIT 1000
) t' INTO fpo_data;
FOR inddata IN SELECT * FROM jsonb_array_elements(fpo_data) LOOP
EXECUTE 'INSERT INTO ' || tb_name || '_' || file_version || '_' || compare_file_version || '_pk(fc_pkey1, fpo_data, fid) VALUES ($1, $2, $3)' USING f_primary_key, inddata, fid;
END LOOP;
ELSE
PERFORM procedure2(tb_name, compare_tb_name, file_version, compare_file_version);
END IF;
return 'Primary Key Generation completed';
END;
$BODY$;
I have not written the complete query. I just written important steps of my query.
My issue is that, in the above query I have create query, insert query and select query and at the end of the stored procedure I have written return statement. If I remove the return all my steps create query, insert query and select query are failing and if I write return then it is not going to procedure2. What is the correct process to run this procedure?
I am trying to write a plpgsql procedure to perform spatial tiling of a postGIS table. I can perform the operation successfully using the following procedure in which the table names are hardcoded. The procedure loops through the tiles in tile_table and for each tile clips the area_table and inserts it into split_table.
CREATE OR REPLACE PROCEDURE splitbytile()
AS $$
DECLARE
tile RECORD;
BEGIN
FOR tile IN
SELECT tid, geom FROM test_tiles ORDER BY tid
LOOP
INSERT INTO split_table (id, areaname, ttid, geom)
SELECT id, areaname, tile.tid,
CASE WHEN st_within(base.geom, tile.geom) THEN st_multi(base.geom)
ELSE st_multi(st_intersection(base.geom, tile.geom)) END as geom
FROM area_table as base
WHERE st_intersects(base.geom, tile.geom);
COMMIT;
END LOOP;
END;
$$ LANGUAGE 'plpgsql';
Having tested this successfully, now I need to convert it to a dynamic procedure where I can provide the table names as parameters. I tried the following partial conversion, using format() for inside of loop:
CREATE OR REPLACE PROCEDURE splitbytile(in_table text, grid_table text, split_table text)
AS $$
DECLARE
tile RECORD;
BEGIN
FOR tile IN
EXECUTE format('SELECT tid, geom FROM %I ORDER BY tid', grid_table)
LOOP
EXECUTE
FORMAT(
'INSERT INTO %1$I (id, areaname, ttid, geom)
SELECT id, areaname, tile.tid,
CASE WHEN st_within(base.geom, tile.geom) THEN st_multi(base.geom)
ELSE st_multi(st_intersection(base.geom, tile.geom)) END as geom
FROM %2$I as base
WHERE st_intersects(base.geom, tile.geom)', split_table, in_table
);
COMMIT;
END LOOP;
END;
$$ LANGUAGE 'plpgsql';
But it throws an error
missing FROM-clause entry for table "tile"
So, how can I convert the procedure to a dynamic one? More specifically, how can I use the record data type (tile) returned by the for loop inside the loop? Note that it works when format is not used.
You can use EXECUTE ... USING to supply parameters to a dynamic query:
EXECUTE
format(
'SELECT r FROM %I WHERE c = $1.val',
table_name
)
INTO result_var
USING record_var;
The first argument to USING will be used for $1, the second for $2 and so on.
See the documentation for details.
Personally I use somehow different way to create dynamic functions. By concatination and execute function. You can also do like this.
CREATE OR REPLACE FUNCTION splitbytile()
RETURNS void AS $$
declare
result1 text;
table_name text := 'test_tiles';
msi text := '+7 9912 231';
msi text := 'Hello world';
code text := 'code_name';
_operator_id integer := 2;
begin
query1 := 'SELECT msisdn from ' || table_name || ' where msisdn = ''' || msi::text ||''';';
query2 := 'INSERT INTO ' || table_name || '(msisdn,usage,body,pr_code,status,sent_date,code_type,operator_id)
VALUES( ''' || msi::text || ''',' || true || ',''' || _body::text || ''',''' || code::text || ''',' || false || ',''' || time_now || ''',' || kod_type || ',' || _operator_id ||');';
execute query1 into result1;
execute query2;
END;
$function$
You just make your query as text then anywhere you want you can execute it. Maybe by checking result1 value inside If statement or smth like that.
I have some function on PostgreSQL 9.6 returning a cursor (refcursor):
CREATE OR REPLACE FUNCTION public.test_returning_cursor()
RETURNS refcursor
IMMUTABLE
LANGUAGE plpgsql
AS $$
DECLARE
_ref refcursor = 'test_returning_cursor_ref1';
BEGIN
OPEN _ref FOR
SELECT 'a' :: text AS col1
UNION
SELECT 'b'
UNION
SELECT 'c';
RETURN _ref;
END
$$;
I need to write another function in which a temp table is created and all data from this refcursor are inserted to it. But INSERT INTO ... FETCH ALL FROM ... seems to be impossible. Such function can't be compiled:
CREATE OR REPLACE FUNCTION public.test_insert_from_cursor()
RETURNS table(col1 text)
IMMUTABLE
LANGUAGE plpgsql
AS $$
BEGIN
CREATE TEMP TABLE _temptable (
col1 text
) ON COMMIT DROP;
INSERT INTO _temptable (col1)
FETCH ALL FROM "test_returning_cursor_ref1";
RETURN QUERY
SELECT col1
FROM _temptable;
END
$$;
I know that I can use:
FOR _rec IN
FETCH ALL FROM "test_returning_cursor_ref1"
LOOP
INSERT INTO ...
END LOOP;
But is there better way?
Unfortunately, INSERT and SELECT don't have access to cursors as a whole.
To avoid expensive single-row INSERT, you could have intermediary functions with RETURNS TABLE and return the cursor as table with RETURN QUERY. See:
Return a query from a function?
CREATE OR REPLACE FUNCTION f_cursor1_to_tbl()
RETURNS TABLE (col1 text) AS
$func$
BEGIN
-- MOVE BACKWARD ALL FROM test_returning_cursor_ref1; -- optional, see below
RETURN QUERY
FETCH ALL FROM test_returning_cursor_ref1;
END
$func$ LANGUAGE plpgsql; -- not IMMUTABLE
Then create the temporary table(s) directly like:
CREATE TEMP TABLE t1 ON COMMIT DROP
AS SELECT * FROM f_cursor1_to_tbl();
See:
Creating temporary tables in SQL
Still not very elegant, but much faster than single-row INSERT.
Note: Since the source is a cursor only the first call succeeds. Executing the function a second time would return an empty set. You would need a cursor with the SCROLL option and move to the start for repeated calls.
This function does INSERT INTO from refcursor. It is universal for all the tables. The only requirement is that all columns of table corresponds to columns of refcursor by types and order (not necessary by names).
to_json() does the trick to convert any primitive data types to string with double-quotes "", which are later replaced with ''.
CREATE OR REPLACE FUNCTION public.insert_into_from_refcursor(_table_name text, _ref refcursor)
RETURNS void
LANGUAGE plpgsql
AS $$
DECLARE
_sql text;
_sql_val text = '';
_row record;
_hasvalues boolean = FALSE;
BEGIN
LOOP --for each row
FETCH _ref INTO _row;
EXIT WHEN NOT found; --there are no rows more
_hasvalues = TRUE;
SELECT _sql_val || '
(' ||
STRING_AGG(val.value :: text, ',') ||
'),'
INTO _sql_val
FROM JSON_EACH(TO_JSON(_row)) val;
END LOOP;
_sql_val = REPLACE(_sql_val, '"', '''');
_sql_val = TRIM(TRAILING ',' FROM _sql_val);
_sql = '
INSERT INTO ' || _table_name || '
VALUES ' || _sql_val;
--RAISE NOTICE 'insert_into_from_refcursor(): SQL is: %', _sql;
IF _hasvalues THEN --to avoid error when trying to insert 0 values
EXECUTE (_sql);
END IF;
END;
$$;
Usage:
CREATE TABLE public.table1 (...);
PERFORM my_func_opening_refcursor();
PERFORM public.insert_into_from_refcursor('public.table1', 'name_of_refcursor_portal'::refcursor);
where my_func_opening_refcursor() contains
DECLARE
_ref refcursor = 'name_of_refcursor_portal';
OPEN _ref FOR
SELECT ...;
I have a few db tables.
I want write universtal postgres function on copy rows to history tables
I have tables:
table1
table1_h
table2
table2_h
I wrote function (with help stackoverflow)
CREATE OR REPLACE FUNCTION copy_history_f() RETURNS TRIGGER AS
$BODY$
DECLARE
tablename_h text:= TG_TABLE_NAME || '_h';
BEGIN
EXECUTE 'INSERT INTO ' || quote_ident(TG_TABLE_SCHEMA) || '.' || quote_ident(tablename_h) || ' VALUES (' || OLD.* ||')';
RETURN NULL;
END;
$BODY$
LANGUAGE plpgsql VOLATILE;
And functions was create, but after update is error.
ERROR: syntax error at or near ","
ROW 1: ...RT INTO table1_h VALUES ((12,,,0,,"Anto...
I know where is error in this insert but I don't know how I repair that.
Structure tables table1 and table1_h are identical but table1_h has one more column (id_h)
Can you help me, how I have create psql function?
Thnak you.
drop table if exists t;
drop table if exists t_h;
drop function if exists ftg();
create table t(i serial, x numeric);
insert into t(x) values(1.1),(2.2);
create table t_h(i int, x numeric);
create function ftg() returns trigger language plpgsql as $ftg$
declare
tablename_h text:= TG_TABLE_NAME || '_h';
begin
execute format($q$ insert into %I.%I select $1.*; $q$, TG_TABLE_SCHEMA, tablename_h) using old;
return null;
end $ftg$;
create trigger tg_t after delete on t for each row execute procedure ftg();
delete from t where i = 1;
select * from t_h;
dbfiddle
Update It solves your problem, but I think that you want to have a bit more info in your history tables. It will be more complex a bit:
drop table if exists t;
drop table if exists t_h;
drop function if exists ftg();
create table t(i serial, x numeric);
insert into t(x) values(1.1),(2.2);
create table t_h(
hi serial, -- just ID
hd timestamp, -- timestamp
hu text, -- user who made changes
ha text, -- action
i int, x numeric
);
create function ftg() returns trigger language plpgsql as $ftg$
declare
tablename_h text:= TG_TABLE_NAME || '_h';
begin
execute format(
$q$
insert into %I.%I
select
nextval(%L || '_hi_seq'),
clock_timestamp(),
current_user,
%L,
$1.*
$q$, TG_TABLE_SCHEMA, tablename_h, tablename_h, TG_OP) using old;
return null;
end $ftg$;
create trigger tg_t after delete or update on t for each row execute procedure ftg();
update t set x = x * 2;
update t set x = x * 2 where i = 2;
delete from t where i = 1;
select * from t_h;
dbfiddle
I assume you are inserting the 'old' values from table1 into table1_h.
The additional column is your problem. When you using an insert without naming columns you must use a matching number and type for the insert.
You must use column referencing.
eg.
Insert into table1_h(column1, column2, column3)
values (a,b,c)
Consider a default value for the additional column in table table1_h.