Pdo: alter table ıf not exısts [duplicate]

I want to say do nothing if there is a column in the table, otherwise add the column, but I couldn’t do it.
I want to do this with PHP and PDO.

This works. But it doesn’t check if the column exists in the table.

$sorgu = $baglanti->prepare("ALTER TABLE gecici ADD Email1 varchar(255)");
$sorgu->execute();

This does not work.

$sorgu = $baglanti->prepare("ALTER TABLE gecici ADD COLUMN IF NOT EXISTS Email1 varchar(255)");
$sorgu->execute();

Thanks in advance for your help.