Good night, I have a request table, which has a FK client_id, this client-id, may possibly be null, but when marking that fk can be null, myslq does not accept, it marks as in null and I define a default value . What can it be?
ALTER TABLE tabela . teste
DROP FOREIGN KEY fk_pedido_cliente1 ;
ALTER TABLE teste . pedido
CHANGE COLUMN id_cliente id_cliente INT (11) NULL;
ALTER TABLE teste . pedido
ADD CONSTRAINT fk_pedido_cliente1
FOREIGN KEY (% with%)
REFERENCES id_cliente . teste ( cliente )
ON DELETE NO ACTION
ON UPDATE NO ACTION;