INSERT and UPDATE in one query MYSQL

Question

I have a simple INSERT query that is run on event click of a button, this gets variables and inserts them into order table.

I also would like to UPDATE my <

Answer 1

If you'll go with a trigger approach then you'll need two triggers (for insert and delete)

CREATE TRIGGER tg_ai_orders
AFTER INSERT ON orders
FOR EACH ROW
  UPDATE bands 
     SET stock = stock - 1
   WHERE band_id = NEW.band_id;

CREATE TRIGGER tg_ad_orders
AFTER DELETE ON orders
FOR EACH ROW
  UPDATE bands 
     SET stock = stock + 1
   WHERE band_id = OLD.band_id;

Here is SQLFiddle demo