MySQL kombinera två kolumner och lägg till en ny kolumn

Skapa kolumnen:

ALTER TABLE yourtable ADD COLUMN combined VARCHAR(50);

Uppdatera de aktuella värdena:

UPDATE yourtable SET combined = CONCAT(zipcode, ' - ', city, ', ', state);

Uppdatera alla framtida värden automatiskt:

CREATE TRIGGER insert_trigger
BEFORE INSERT ON yourtable
FOR EACH ROW
SET new.combined = CONCAT(new.zipcode, ' - ', new.city, ', ', new.state);

CREATE TRIGGER update_trigger
BEFORE UPDATE ON yourtable
FOR EACH ROW
SET new.combined = CONCAT(new.zipcode, ' - ', new.city, ', ', new.state);