In postgres how can I delete all columns that share the same prefix - postgresql

Question

I have been using the following code for dropping all tables that share the same prefix (in this case delete all tables that their name starts with 'supenh_'):
DO
$do$
DECLARE
_tbl text;
BEGIN
FOR _tbl IN
SELECT quote_ident(table_schema) || '.'
|| quote_ident(table_name) -- escape identifier and schema-qualify!
FROM information_schema.tables
WHERE table_name LIKE 'supenh_' || '%' -- your table name prefix
AND table_schema NOT LIKE 'pg_%' -- exclude system schemas
LOOP
-- RAISE NOTICE '%',
EXECUTE
'DROP TABLE ' || _tbl;
END LOOP;
END
$do$;
Is there a way to amend this code / or to use a different script in order to delete from one specific table all the columns that start with the same prefix (for example, 'patient1_') ?

Answer 1

You could write it as PL/pgSQL function:
CREATE OR REPLACE FUNCTION drop_columns_with_prefix(tbl_name TEXT, column_prefix TEXT) RETURNS VOID AS
$BODY$
DECLARE
_column TEXT;
BEGIN
FOR _column IN
SELECT quote_ident(column_name)
FROM information_schema.columns
WHERE table_name = tbl_name
AND column_name LIKE column_prefix || '%'
AND table_schema NOT LIKE 'pg_%'
LOOP
-- RAISE NOTICE '%',
EXECUTE
'ALTER TABLE ' || tbl_name || ' DROP COLUMN ' || _column;
END LOOP;
END
$BODY$
LANGUAGE plpgsql VOLATILE;
Call it using:
SELECT drop_columns_with_prefix('tbl_name', 'prefix_');
Or if you don't want to use it as a function:
DO
$do$
DECLARE
_column TEXT;
BEGIN
FOR _column IN
SELECT quote_ident(column_name)
FROM information_schema.columns
WHERE table_name = 'tbl_name'
AND column_name LIKE 'prefix_%'
AND table_schema NOT LIKE 'pg_%'
LOOP
-- RAISE NOTICE '%',
EXECUTE
'ALTER TABLE tbl_name DROP COLUMN ' || _column;
END LOOP;
END
$do$