Is it possible to search every column of every table for a particular value in PostgreSQL?
A similar question is available here for Oracle.
How about dumping the contents of the database, then using grep?
$ pg_dump --data-only --inserts -U postgres your-db-name > a.tmp
$ grep United a.tmp
INSERT INTO countries VALUES ('US', 'United States');
INSERT INTO countries VALUES ('GB', 'United Kingdom');
The same utility, pg_dump, can include column names in the output. Just change --inserts to --column-inserts. That way you can search for specific column names, too. But if I were looking for column names, I'd probably dump the schema instead of the data.
$ pg_dump --data-only --column-inserts -U postgres your-db-name > a.tmp
$ grep country_code a.tmp
INSERT INTO countries (iso_country_code, iso_country_name) VALUES ('US', 'United States');
INSERT INTO countries (iso_country_code, iso_country_name) VALUES ('GB', 'United Kingdom');
Here's a pl/pgsql function that locates records where any column contains a specific value.
It takes as arguments the value to search in text format, an array of table names to search into (defaults to all tables) and an array of schema names (defaults all schema names).
It returns a table structure with schema, name of table, name of column and pseudo-column ctid (non-durable physical location of the row in the table, see System Columns)
CREATE OR REPLACE FUNCTION search_columns(
needle text,
haystack_tables name[] default '{}',
haystack_schema name[] default '{}'
)
RETURNS table(schemaname text, tablename text, columnname text, rowctid text)
AS $$
begin
FOR schemaname,tablename,columnname IN
SELECT c.table_schema,c.table_name,c.column_name
FROM information_schema.columns c
JOIN information_schema.tables t ON
(t.table_name=c.table_name AND t.table_schema=c.table_schema)
JOIN information_schema.table_privileges p ON
(t.table_name=p.table_name AND t.table_schema=p.table_schema
AND p.privilege_type='SELECT')
JOIN information_schema.schemata s ON
(s.schema_name=t.table_schema)
WHERE (c.table_name=ANY(haystack_tables) OR haystack_tables='{}')
AND (c.table_schema=ANY(haystack_schema) OR haystack_schema='{}')
AND t.table_type='BASE TABLE'
LOOP
FOR rowctid IN
EXECUTE format('SELECT ctid FROM %I.%I WHERE cast(%I as text)=%L',
schemaname,
tablename,
columnname,
needle
)
LOOP
-- uncomment next line to get some progress report
-- RAISE NOTICE 'hit in %.%', schemaname, tablename;
RETURN NEXT;
END LOOP;
END LOOP;
END;
$$ language plpgsql;
See also the version on github based on the same principle but adding some speed and reporting improvements.
Examples of use in a test database:
Search in all tables within public schema:
select * from search_columns('foobar');
schemaname | tablename | columnname | rowctid
------------+-----------+------------+---------
public | s3 | usename | (0,11)
public | s2 | relname | (7,29)
public | w | body | (0,2)
(3 rows)
Search in a specific table:
select * from search_columns('foobar','{w}');
schemaname | tablename | columnname | rowctid
------------+-----------+------------+---------
public | w | body | (0,2)
(1 row)
Search in a subset of tables obtained from a select:
select * from search_columns('foobar', array(select table_name::name from information_schema.tables where table_name like 's%'), array['public']);
schemaname | tablename | columnname | rowctid
------------+-----------+------------+---------
public | s2 | relname | (7,29)
public | s3 | usename | (0,11)
(2 rows)
Get a result row with the corresponding base table and and ctid:
select * from public.w where ctid='(0,2)';
title | body | tsv
-------+--------+---------------------
toto | foobar | 'foobar':2 'toto':1
Variants
To test against a regular expression instead of strict equality, like grep, this part of the query:
SELECT ctid FROM %I.%I WHERE cast(%I as text)=%L
may be changed to:
SELECT ctid FROM %I.%I WHERE cast(%I as text) ~ %L
For case insensitive comparisons, you could write:
SELECT ctid FROM %I.%I WHERE lower(cast(%I as text)) = lower(%L)
to search every column of every table for a particular value
This does not define how to match exactly.
Nor does it define what to return exactly.
Assuming:
Find any row with any column containing the given value in its text representation - as opposed to equaling the given value.
Return the table name (regclass) and the tuple ID (ctid), because that's simplest.
Here is a dead simple, fast and slightly dirty way:
CREATE OR REPLACE FUNCTION search_whole_db(_like_pattern text)
RETURNS TABLE(_tbl regclass, _ctid tid) AS
$func$
BEGIN
FOR _tbl IN
SELECT c.oid::regclass
FROM pg_class c
JOIN pg_namespace n ON n.oid = relnamespace
WHERE c.relkind = 'r' -- only tables
AND n.nspname !~ '^(pg_|information_schema)' -- exclude system schemas
ORDER BY n.nspname, c.relname
LOOP
RETURN QUERY EXECUTE format(
'SELECT $1, ctid FROM %s t WHERE t::text ~~ %L'
, _tbl, '%' || _like_pattern || '%')
USING _tbl;
END LOOP;
END
$func$ LANGUAGE plpgsql;
Call:
SELECT * FROM search_whole_db('mypattern');
Provide the search pattern without enclosing %.
Why slightly dirty?
If separators and decorators for the row in text representation can be part of the search pattern, there can be false positives:
column separator: , by default
whole row is enclosed in parentheses:()
some values are enclosed in double quotes "
\ may be added as escape char
And the text representation of some columns may depend on local settings - but that ambiguity is inherent to the question, not to my solution.
Each qualifying row is returned once only, even when it matches multiple times (as opposed to other answers here).
This searches the whole DB except for system catalogs. Will typically take a long time to finish. You might want to restrict to certain schemas / tables (or even columns) like demonstrated in other answers. Or add notices and a progress indicator, also demonstrated in another answer.
The regclass object identifier type is represented as table name, schema-qualified where necessary to disambiguate according to the current search_path:
Find the referenced table name using table, field and schema name
What is the ctid?
How do I decompose ctid into page and row numbers?
You might want to escape characters with special meaning in the search pattern. See:
Escape function for regular expression or LIKE patterns
There is a way to achieve this without creating a function or using an external tool. By using Postgres' query_to_xml() function that can dynamically run a query inside another query, it's possible to search a text across many tables. This is based on my answer to retrieve the rowcount for all tables:
To search for the string foo across all tables in a schema, the following can be used:
with found_rows as (
select format('%I.%I', table_schema, table_name) as table_name,
query_to_xml(format('select to_jsonb(t) as table_row
from %I.%I as t
where t::text like ''%%foo%%'' ', table_schema, table_name),
true, false, '') as table_rows
from information_schema.tables
where table_schema = 'public'
)
select table_name, x.table_row
from found_rows f
left join xmltable('//table/row'
passing table_rows
columns
table_row text path 'table_row') as x on true
Note that the use of xmltable requires Postgres 10 or newer. For older Postgres version, this can be also done using xpath().
with found_rows as (
select format('%I.%I', table_schema, table_name) as table_name,
query_to_xml(format('select to_jsonb(t) as table_row
from %I.%I as t
where t::text like ''%%foo%%'' ', table_schema, table_name),
true, false, '') as table_rows
from information_schema.tables
where table_schema = 'public'
)
select table_name, x.table_row
from found_rows f
cross join unnest(xpath('/table/row/table_row/text()', table_rows)) as r(data)
The common table expression (WITH ...) is only used for convenience. It loops through all tables in the public schema. For each table the following query is run through the query_to_xml() function:
select to_jsonb(t)
from some_table t
where t::text like '%foo%';
The where clause is used to make sure the expensive generation of XML content is only done for rows that contain the search string. This might return something like this:
<table xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<row>
<table_row>{"id": 42, "some_column": "foobar"}</table_row>
</row>
</table>
The conversion of the complete row to jsonb is done, so that in the result one could see which value belongs to which column.
The above might return something like this:
table_name | table_row
-------------+----------------------------------------
public.foo | {"id": 1, "some_column": "foobar"}
public.bar | {"id": 42, "another_column": "barfoo"}
Online example for Postgres 10+
Online example for older Postgres versions
Without storing a new procedure you can use a code block and execute to obtain a table of occurences. You can filter results by schema, table or column name.
DO $$
DECLARE
value int := 0;
sql text := 'The constructed select statement';
rec1 record;
rec2 record;
BEGIN
DROP TABLE IF EXISTS _x;
CREATE TEMPORARY TABLE _x (
schema_name text,
table_name text,
column_name text,
found text
);
FOR rec1 IN
SELECT table_schema, table_name, column_name
FROM information_schema.columns
WHERE table_name <> '_x'
AND UPPER(column_name) LIKE UPPER('%%')
AND table_schema <> 'pg_catalog'
AND table_schema <> 'information_schema'
AND data_type IN ('character varying', 'text', 'character', 'char', 'varchar')
LOOP
sql := concat('SELECT ', rec1."column_name", ' AS "found" FROM ',rec1."table_schema" , '.',rec1."table_name" , ' WHERE UPPER(',rec1."column_name" , ') LIKE UPPER(''','%my_substring_to_find_goes_here%' , ''')');
RAISE NOTICE '%', sql;
BEGIN
FOR rec2 IN EXECUTE sql LOOP
RAISE NOTICE '%', sql;
INSERT INTO _x VALUES (rec1."table_schema", rec1."table_name", rec1."column_name", rec2."found");
END LOOP;
EXCEPTION WHEN OTHERS THEN
END;
END LOOP;
END; $$;
SELECT * FROM _x;
If you're using IntelliJ add your DB to Database view then right click on databases and select full text search, it will list all tables and all fields for your specific text.
And if someone think it could help. Here is #Daniel Vérité's function, with another param that accept names of columns that can be used in search. This way it decrease the time of processing. At least in my test it reduced a lot.
CREATE OR REPLACE FUNCTION search_columns(
needle text,
haystack_columns name[] default '{}',
haystack_tables name[] default '{}',
haystack_schema name[] default '{public}'
)
RETURNS table(schemaname text, tablename text, columnname text, rowctid text)
AS $$
begin
FOR schemaname,tablename,columnname IN
SELECT c.table_schema,c.table_name,c.column_name
FROM information_schema.columns c
JOIN information_schema.tables t ON
(t.table_name=c.table_name AND t.table_schema=c.table_schema)
WHERE (c.table_name=ANY(haystack_tables) OR haystack_tables='{}')
AND c.table_schema=ANY(haystack_schema)
AND (c.column_name=ANY(haystack_columns) OR haystack_columns='{}')
AND t.table_type='BASE TABLE'
LOOP
EXECUTE format('SELECT ctid FROM %I.%I WHERE cast(%I as text)=%L',
schemaname,
tablename,
columnname,
needle
) INTO rowctid;
IF rowctid is not null THEN
RETURN NEXT;
END IF;
END LOOP;
END;
$$ language plpgsql;
Bellow is an example of usage of the search_function created above.
SELECT * FROM search_columns('86192700'
, array(SELECT DISTINCT a.column_name::name FROM information_schema.columns AS a
INNER JOIN information_schema.tables as b ON (b.table_catalog = a.table_catalog AND b.table_schema = a.table_schema AND b.table_name = a.table_name)
WHERE
a.column_name iLIKE '%cep%'
AND b.table_type = 'BASE TABLE'
AND b.table_schema = 'public'
)
, array(SELECT b.table_name::name FROM information_schema.columns AS a
INNER JOIN information_schema.tables as b ON (b.table_catalog = a.table_catalog AND b.table_schema = a.table_schema AND b.table_name = a.table_name)
WHERE
a.column_name iLIKE '%cep%'
AND b.table_type = 'BASE TABLE'
AND b.table_schema = 'public')
);
Here's #Daniel Vérité's function with progress reporting functionality.
It reports progress in three ways:
by RAISE NOTICE;
by decreasing value of supplied {progress_seq} sequence from
{total number of colums to search in} down to 0;
by writing the progress along with found tables into text file,
located in c:\windows\temp\{progress_seq}.txt.
_
CREATE OR REPLACE FUNCTION search_columns(
needle text,
haystack_tables name[] default '{}',
haystack_schema name[] default '{public}',
progress_seq text default NULL
)
RETURNS table(schemaname text, tablename text, columnname text, rowctid text)
AS $$
DECLARE
currenttable text;
columnscount integer;
foundintables text[];
foundincolumns text[];
begin
currenttable='';
columnscount = (SELECT count(1)
FROM information_schema.columns c
JOIN information_schema.tables t ON
(t.table_name=c.table_name AND t.table_schema=c.table_schema)
WHERE (c.table_name=ANY(haystack_tables) OR haystack_tables='{}')
AND c.table_schema=ANY(haystack_schema)
AND t.table_type='BASE TABLE')::integer;
PERFORM setval(progress_seq::regclass, columnscount);
FOR schemaname,tablename,columnname IN
SELECT c.table_schema,c.table_name,c.column_name
FROM information_schema.columns c
JOIN information_schema.tables t ON
(t.table_name=c.table_name AND t.table_schema=c.table_schema)
WHERE (c.table_name=ANY(haystack_tables) OR haystack_tables='{}')
AND c.table_schema=ANY(haystack_schema)
AND t.table_type='BASE TABLE'
LOOP
EXECUTE format('SELECT ctid FROM %I.%I WHERE cast(%I as text)=%L',
schemaname,
tablename,
columnname,
needle
) INTO rowctid;
IF rowctid is not null THEN
RETURN NEXT;
foundintables = foundintables || tablename;
foundincolumns = foundincolumns || columnname;
RAISE NOTICE 'FOUND! %, %, %, %', schemaname,tablename,columnname, rowctid;
END IF;
IF (progress_seq IS NOT NULL) THEN
PERFORM nextval(progress_seq::regclass);
END IF;
IF(currenttable<>tablename) THEN
currenttable=tablename;
IF (progress_seq IS NOT NULL) THEN
RAISE NOTICE 'Columns left to look in: %; looking in table: %', currval(progress_seq::regclass), tablename;
EXECUTE 'COPY (SELECT unnest(string_to_array(''Current table (column ' || columnscount-currval(progress_seq::regclass) || ' of ' || columnscount || '): ' || tablename || '\n\nFound in tables/columns:\n' || COALESCE(
(SELECT string_agg(c1 || '/' || c2, '\n') FROM (SELECT unnest(foundintables) AS c1,unnest(foundincolumns) AS c2) AS t1)
, '') || ''',''\n''))) TO ''c:\WINDOWS\temp\' || progress_seq || '.txt''';
END IF;
END IF;
END LOOP;
END;
$$ language plpgsql;
-- Below function will list all the tables which contain a specific string in the database
select TablesCount(‘StringToSearch’);
--Iterates through all the tables in the database
CREATE OR REPLACE FUNCTION **TablesCount**(_searchText TEXT)
RETURNS text AS
$$ -- here start procedural part
DECLARE _tname text;
DECLARE cnt int;
BEGIN
FOR _tname IN SELECT table_name FROM information_schema.tables where table_schema='public' and table_type='BASE TABLE' LOOP
cnt= getMatchingCount(_tname,Columnames(_tname,_searchText));
RAISE NOTICE 'Count% ', CONCAT(' ',cnt,' Table name: ', _tname);
END LOOP;
RETURN _tname;
END;
$$ -- here finish procedural part
LANGUAGE plpgsql; -- language specification
-- Returns the count of tables for which the condition is met.
-- For example, if the intended text exists in any of the fields of the table,
-- then the count will be greater than 0. We can find the notifications
-- in the Messages section of the result viewer in postgres database.
CREATE OR REPLACE FUNCTION **getMatchingCount**(_tname TEXT, _clause TEXT)
RETURNS int AS
$$
Declare outpt text;
BEGIN
EXECUTE 'Select Count(*) from '||_tname||' where '|| _clause
INTO outpt;
RETURN outpt;
END;
$$ LANGUAGE plpgsql;
--Get the fields of each table. Builds the where clause with all columns of a table.
CREATE OR REPLACE FUNCTION **Columnames**(_tname text,st text)
RETURNS text AS
$$ -- here start procedural part
DECLARE
_name text;
_helper text;
BEGIN
FOR _name IN SELECT column_name FROM information_schema.Columns WHERE table_name =_tname LOOP
_name=CONCAT('CAST(',_name,' as VarChar)',' like ','''%',st,'%''', ' OR ');
_helper= CONCAT(_helper,_name,' ');
END LOOP;
RETURN CONCAT(_helper, ' 1=2');
END;
$$ -- here finish procedural part
LANGUAGE plpgsql; -- language specification
Is there any way to replace the table name in a query with value stored in another table ? This is in postgres sql
Eg
Meta_table
col1 | col 2
Table 1 | val1
Table 2 | val2
My requirement
select *
from (select col1 from meta_table where col2 = val2)
Probably the most flexible and efficient way is dynamically creating a temporary view using function:
create or replace function f_prepare(tname text, vname text) returns text language plpgsql as $$
begin
execute format(
'create or replace temporary view %I as select * from %I',
vname, tname);
return vname;
end $$;
Then you can use the created view in usual way, for example;
select f_prepare('pg_class', 'v_class');
select * from v_class where relname = 'pg_database'; -- Index on the source table will be used here
and using your code:
select f_prepare((select col1 from meta_table where col2 = 'val2'), 'v');
select * from v;
And as any other temporary objects, created views will not conflict with other sessions and will be dropped on disconnect.
If you want to change the table name of a table, then you can just update the relname column in table pg_class.
But for this, you need admin access to the Postgresql.
The query goes like:-
update pg_class set relname='new_table_name' where relname='old_table_name';
So to do this in single line, You can do like this:
update pg_class set relname=(select col1 from meta_table where col2 = val2) where relname='old_table_name';
You can use Do statement with cursor:
Try This:
DO $$
DECLARE
_query text;
_cursor CONSTANT refcursor := '_cursor';
BEGIN
_query := 'SELECT * FROM '|| (select col1 from meta_table where col2 = 'val1');
OPEN _cursor FOR EXECUTE _query;
END
$$;
FETCH ALL FROM _cursor;
I have the below function compiled successfully. When I do select schema.funtion_name();, the function gets executed but there are no rows inserted in the table schema.table_insert:
CREATE OR REPLACE FUNCTION schema.function_name()
RETURNS void AS
$BODY$
DECLARE cur_1 CURSOR FOR
Select col1 from schema.table1
union
select col1 from schema.table2
union
select col1 from schema.table3
union
select col1 from schema.table4;
BEGIN
FOR rec_i in cur_1 LOOP
insert into schema.table_insert (col1,col2,col3)
select col1,col2,col3
from schema.view
where col1=rec_i.col1
commit;
END LOOP;
END;
$BODY$
LANGUAGE plpgsql STABLE
The select in cursor cur_1 returns more than 900 000 records. When I use the insert statement separately for single record, the record gets inserted in the table.
I have the below function compiled successfully.
No, you haven't.
For starters, plpgsql functions are not "compiled". On creation, only superficial syntax checks are done, then the function body is stored as is. No compilation. Late binding. Nested SQL statements are treated as prepared statements.
That aside, the function you display cannot be created at all. It is syntactical nonsense. Missing semicolon after the INSERT. COMMIT does not make sense and is not allowed in plpgsql. You do not need a cursor for this. Nor looping. Use a simple SQL statement:
INSERT INTO schema.table_insert (col1, col2, col3)
SELECT v.col1, v.col2, v.col3
FROM schema.view v
JOIN (
SELECT col1 FROM schema.table1
UNION
SELECT col1 FROM schema.table2
UNION
SELECT col1 FROM schema.table3
UNION
SELECT col1 FROM schema.table4;
) sub USING (col1);
Equivalent, may be faster:
INSERT INTO schema.table_insert (col1, col2, col3)
SELECT v.col1, v.col2, v.col3
FROM schema.view v
WHERE EXISTS (SELECT 1 schema.table1 WHERE col1 = v.col1)
OR EXISTS (SELECT 1 schema.table2 WHERE col1 = v.col1)
OR EXISTS (SELECT 1 schema.table3 WHERE col1 = v.col1)
OR EXISTS (SELECT 1 schema.table4 WHERE col1 = v.col1);
Can be wrapped up in a function, but plpgsql is overkill. And STABLE, would be wrong for a function containing an INSERT. I suggest a plain SQL function and VOLATILE is the default and correct for this.
CREATE OR REPLACE FUNCTION schema.function_name()
RETURNS void AS
$func$
INSERT ...
$func$ LANGUAGE sql;
I have multiple tables with each two rows of interest: connection_node_start_id and connection_node_end_id. My goal is to get a collection of all those IDs, either as a flat ARRAY or as a new TABLE consisting of one row.
Example output ARRAY:
result = {1,4,7,9,2,5}
Example output TABLE:
IDS
-------
1
4
7
9
2
5
My fist attempt is somewhat clumsy and does not work properly as the SELECT statement just returns one row. It seems there must be a simple way to do this, can someone point me into the right direction?
CREATE OR REPLACE FUNCTION get_connection_nodes(anyarray)
RETURNS anyarray AS
$$
DECLARE
table_name varchar;
result integer[];
sel integer[];
BEGIN
FOREACH table_name IN ARRAY $1
LOOP
RAISE NOTICE 'table_name(%)',table_name;
EXECUTE 'SELECT ARRAY[connection_node_end_id,
connection_node_start_id] FROM ' || table_name INTO sel;
RAISE NOTICE 'sel(%)',sel;
result := array_cat(result, sel);
END LOOP;
RETURN result;
END
$$
LANGUAGE 'plpgsql';
Test table:
connection_node_start_id | connection_node_end_id
--------------------------------------------------
1 | 4
7 | 9
Call:
SELECT get_connection_nodes(ARRAY['test_table']);
Result:
{1,4} -- only 1st row, rest is missing
For Postgres 9.3+
CREATE OR REPLACE FUNCTION get_connection_nodes(text[])
RETURNS TABLE (ids int) AS
$func$
DECLARE
_tbl text;
BEGIN
FOREACH _tbl IN ARRAY $1
LOOP
RETURN QUERY EXECUTE format('
SELECT t.id
FROM %I, LATERAL (VALUES (connection_node_start_id)
, (connection_node_end_id)) t(id)'
, _tbl);
END LOOP;
END
$func$ LANGUAGE plpgsql;
Related answer on dba.SE:
SELECT DISTINCT on multiple columns
Or drop the loop and concatenate a single query. Probably fastest:
CREATE OR REPLACE FUNCTION get_connection_nodes2(text[])
RETURNS TABLE (ids int) AS
$func$
BEGIN
RETURN QUERY EXECUTE (
SELECT string_agg(format(
'SELECT t.id FROM %I, LATERAL (VALUES (connection_node_start_id)
, (connection_node_end_id)) t(id)'
, tbl), ' UNION ALL ')
FROM unnest($1) tbl
);
END
$func$ LANGUAGE plpgsql;
Related:
Loop through like tables in a schema
LATERAL was introduced with Postgres 9.3.
For older Postgres
You can use the set-returning function unnest() in the SELECT list, too:
CREATE OR REPLACE FUNCTION get_connection_nodes2(text[])
RETURNS TABLE (ids int) AS
$func$
BEGIN
RETURN QUERY EXECUTE (
SELECT string_agg(
'SELECT unnest(ARRAY[connection_node_start_id
, connection_node_end_id]) FROM ' || tbl
, ' UNION ALL '
)
FROM (SELECT quote_ident(tbl) AS tbl FROM unnest($1) tbl) t
);
END
$func$ LANGUAGE plpgsql;
Should work with pg 8.4+ (or maybe even older). Works with current Postgres (9.4) as well, but LATERAL is much cleaner.
Or make it very simple:
CREATE OR REPLACE FUNCTION get_connection_nodes3(text[])
RETURNS TABLE (ids int) AS
$func$
BEGIN
RETURN QUERY EXECUTE (
SELECT string_agg(format(
'SELECT connection_node_start_id FROM %1$I
UNION ALL
SELECT connection_node_end_id FROM %1$I'
, tbl), ' UNION ALL ')
FROM unnest($1) tbl
);
END
$func$ LANGUAGE plpgsql;
format() was introduced with pg 9.1.
Might be a bit slower with big tables because each table is scanned once for every column (so 2 times here). Sort order in the result is different, too - but that does not seem to matter for you.
Be sure to sanitize escape identifiers to defend against SQL injection and other illegal syntax. Details:
Table name as a PostgreSQL function parameter
The EXECUTE ... INTO statement can only return data from a single row:
If multiple rows are returned, only the first will be assigned to the INTO variable.
In order to concatenate values from all rows you have to aggregate them first by column and then append the arrays:
EXECUTE 'SELECT array_agg(connection_node_end_id) ||
array_agg(connection_node_start_id) FROM ' || table_name INTO sel;
You're probably looking for something like this:
CREATE OR REPLACE FUNCTION d (tblname TEXT [])
RETURNS TABLE (c INTEGER) AS $$
DECLARE sql TEXT;
BEGIN
WITH x
AS (SELECT unnest(tblname) AS tbl),
y AS (
SELECT FORMAT('
SELECT connection_node_end_id
FROM %s
UNION ALL
SELECT connection_node_start_id
FROM %s
', tbl, tbl) AS s
FROM x)
SELECT string_agg(s, ' UNION ALL ')
INTO sql
FROM y;
RETURN QUERY EXECUTE sql;
END;$$
LANGUAGE plpgsql;
CREATE TABLE a (connection_node_end_id INTEGER, connection_node_start_id INTEGER);
INSERT INTO A VALUES (1,2);
CREATE TABLE b (connection_node_end_id INTEGER, connection_node_start_id INTEGER);
INSERT INTO B VALUES (100, 101);
SELECT * from d(array['a','b']);
c
-----
1
2
100
101
(4 rows)