Create INSERT statement

Sometimes you might want to create an INSERT statement which reproduces a particular row in a table. It's simple enough to do with the help of a PL/PgSQL function:

CREATE OR REPLACE FUNCTION create_insert_statement(regclass, anyelement) RETURNS text
    LANGUAGE plpgsql
    AS $$
DECLARE
_schemaname text;
_tablename text;
_key text;
_value text;
_columns text[];
_values text[];
BEGIN
SELECT pg_namespace.nspname, pg_class.relname
INTO STRICT _schemaname, _tablename
FROM pg_class
JOIN pg_namespace
    ON (pg_namespace.oid = pg_class.relnamespace)
WHERE pg_class.oid = $1;

FOR _key IN
    SELECT columns.column_name
    FROM information_schema.columns
    WHERE columns.table_schema = _schemaname
      AND columns.table_name = _tablename
    ORDER BY columns.ordinal_position
LOOP
    EXECUTE format($s$SELECT format('%%L', ((($1)::%s).%I))$s$, $1, _key) USING $2 INTO STRICT _value;
    _columns := _columns || _key;
    _values := _values || _value;
END LOOP;
RETURN format('INSERT INTO %s (%s) VALUES (%s)', $1, array_to_string(_columns, ','), array_to_string(_values, ','));
END;
$$;

Then you can call the function like this:

CREATE TABLE mytable(a int, b int);
INSERT INTO mytable VALUES (0, -999);

SELECT create_insert_statement(tableoid, mytable) FROM mytable;

-- returns
--            create_insert_statement            
-------------------------------------------------
-- INSERT INTO mytable (a,b) VALUES ('0','-999')
--(1 row)