Trigger with query data - mysql

Question

I have table with the informations:
INSERT INTO Transferencias
('Origem_Apostador_ID', 'Destino_Apostador_ID', 'Valor_Transferido')
VALUES
('1', '6', '200.00');
And I need to get value '200.00' and sum with the data from another table after this value have been insert on table to this table below:
INSERT INTO Conta
('Apostador_ID', 'Saldo', 'Qtd_Saque', 'Qtd_Deposito', 'Qtd_Transferencia')
VALUES
('1', '700.00', '0', '1', '0');
I have no idea how can I use data from query to do the update on "Saldo" column.

Answer 1

I don`t know if I understood your question correctly, but i think you need something like this:
UPDATE Conta
SET Saldo = Saldo + (SELECT Valor_Transferido FROM Transferencias WHERE Origem_Apostador_ID = '1')
WHERE Apostador_ID = '1';
You can add this code to some trigger if you want to. You can find many examples out there for simple triggers to do the work depending on your database.
TRIGGER EXAMPLE ON MYSQL
CREATE TRIGGER TRG_UPDATE_SALDO BEFORE INSERT ON Transferencias
FOR EACH ROW
BEGIN
IF NEW.Valor_Transferido > 0 THEN
--Increments the destination account
UPDATE Conta
SET Saldo = Saldo + NEW.Valor_Transferido
WHERE Apostador_ID = NEW.Destino_Apostador_ID;
--Subtracts the origin account
UPDATE Conta
SET Saldo = Saldo - NEW.Valor_Transferido
WHERE Apostador_ID = NEW.Origem_Apostador_ID;
END IF;
END;