mysql PHP自动增量列

Question

如何在这些语句中添加名为ID的自动递增列：

$sql = "CREATE TABLE IF NOT EXISTS ".$username." (uid varchar(255), tweet varchar(255))";
$alter = "ALTER TABLE ".$username." ADD UNIQUE (uid)";

由于

Answer 1

$sql = "CREATE TABLE IF NOT EXISTS ".$username." (ID int not null auto_increment primary key, uid varchar(255), tweet varchar(255))";

Answer 2

我愿意

"CREATE TABLE IF NOT EXISTS ".$username." (id MEDIUMINT AUTO_INCREMENT PRIMARY KEY, uid varchar(255) UNIQUE, tweet varchar(255))";