PostgreSQL error code

PostgreSQL error 24000

24000 is the SQLSTATE PostgreSQL reports for invalid cursor state, in class 24, Invalid Cursor State.

SQLSTATE	24000
Condition name	invalid_cursor_state
Class	24 — Invalid Cursor State

Reproduce it, then fix it

WHERE CURRENT OF updates the row the cursor is on, and a freshly declared cursor isn’t on any row yet. FETCH one first. Run the broken query to see the error, then switch to the fixed one. Edit either freely; every run is rolled back.

DECLARE c CURSOR FOR SELECT * FROM products ORDER BY id FOR UPDATE;
UPDATE products SET price = price * 0.9 WHERE CURRENT OF c;

DECLARE c CURSOR FOR SELECT * FROM products ORDER BY id FOR UPDATE;
FETCH c;
UPDATE products SET price = price * 0.9 WHERE CURRENT OF c RETURNING id, name, price;

Source: PostgreSQL documentation, Appendix A