ERROR 1241 (21000): Operand should contain 1 column(s) on simple insert

Question

I keep getting that error

ERROR 1241 (21000): Operand should contain 1 column(s).

I have table Deck which has DeckId, PlayerId, CardId (player and card are foreign keys from table Collection ). And all three are primary key for that table. I am trying to do simple Insert on Deck.

INSERT INTO Deck (DeckId, PlayerId, CardId) 
VALUES (1, 1, 1);

And I keep getting that error. I modeled database with MySql workbench. Deck is dependent on Collection , it has identifying 1:m relationship. I don't know if that may be causing problems.

Here is paste for create schema , triggers . Names are not in English. It is model of DB for card game Hearthstone, dunno if I should use that name, but it is for a school project, I guess professor won't mind.

Answer 1

I found what the mistake was.

It was not problem in insert statement but in create trigger statement. It returned 2 rows instead of 1. Thank you all.