Using join in update command in trigger - mysql

Question

I have 3 tables
'stockMedicina' (farmaciaID,seriemedicina,stock)
'Factura' (farmaciaid,facturaid)
'DetalleFactura' (facturaid,seriemedicina,cantidad)
and i want to update the inventory of stockMedicina which is an int named stock when i insert a new value to detalleFactura. So when i insert a new value in detalleFactura i want to update the inventory of the farmaciaid which is on the factura table to decrease the amount of stock. I have this code but it doesn't work, and i don't know what to do now. :(
DELIMITER $$;
CREATE TRIGGER diminuirStock
AFTER INSERT ON detalleFactura
FOR EACH ROW
BEGIN
UPDATE stockmedicina sm
INNER JOIN factura fa ON sm.farmaciaid = fa.farmacia
INNER JOIN detalleFactura df ON sm.seriemedicina = df.seriemedicina AND fa.facturaID=df.facturaID
SET sm.stock = sm.stock - NEW.cantidad
WHERE sm.FarmaciaID = fa.Farmacia and sm.seriemedicina=NEW.facturaID
END$$
DELIMITER ;
Any thought or help about it would be really helpful :c

Answer 1

Some of your columns have the false column name
Schema (MySQL v8.0)
CREATE TABLE stockMedicina (farmaciaID INT,seriemedicina INT ,stock INT);
INSERT INTO stockMedicina VALUES (1,1,10);
CREATE TABLE Factura (farmaciaid INT, faturaid INT);
INSERT INTO Factura VALUES (1,1);
CREATE TABLE DetalleFactura (facturaid INT ,seriemedicina INT ,cantidad INT);
DELIMITER $$
CREATE TRIGGER diminuirStock
AFTER INSERT ON DetalleFactura
FOR EACH ROW
BEGIN
UPDATE stockMedicina sm
INNER JOIN Factura fa ON sm.farmaciaID = fa.farmaciaid
INNER JOIN DetalleFactura df ON sm.seriemedicina = df.seriemedicina AND fa.faturaid=df.facturaID
SET sm.stock = sm.stock - NEW.cantidad
WHERE sm.FarmaciaID = fa.farmaciaid and sm.seriemedicina=NEW.facturaid;
END$$
DELIMITER ;
INSERT INTO DetalleFactura VALUES (1,1,2)
Query #1
SELECT * FROM stockMedicina;
| farmaciaID | seriemedicina | stock |
| ---------- | ------------- | ----- |
| 1 | 1 | 8 |
View on DB Fiddle