關於「ALTER TABLE ADD KEY」標籤，搜尋引擎有相關的訊息討論：

MySQL 8.0 Reference Manual :: 13.1.9 ALTER TABLE Statementdev.mysql.com › doc › refman › alter-tableMySQL 5.7 Reference Manual :: 13.1.8 ALTER TABLE Statementdev.mysql.com › doc › refman › alter-tableMySQL alter table add column with primary key syntax errorstackoverflow.com ›