SELECT unique SQL關於「MySQL UNIQUE KEY multiple columns」標籤，搜尋引擎有相關的訊息討論：
How do I specify unique constraint for multiple columns in MySQL?stackoverflow.com › questions › how-do-i-specify-unique-...Multiple column unique key allows multiple rows? - MySQL Bugsbugs.mysql.com › bugSQL UNIQUE Constraint - W3Schoolswww.w3schools.com › sql › sql_uniqueUsin