MySQLは2つの列を結合し、新しい列に追加します

列を作成します：

ALTER TABLE yourtable ADD COLUMN combined VARCHAR(50);

現在の値を更新します：

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

今後のすべての値を自動的に更新します：

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);