你做到了:

$qlanguages = "'english,greek'";
$sql1 = "INSERT INTO person (first_name, last_name, languages) 
     VALUES ('$qfirst_name', '$qlast_name', '$qlanguages')";

所以你得到了这个:

$sql1 = "INSERT INTO person (first_name, last_name, languages) 
     VALUES ('qfirst_name', 'qlast_name', ''english,greek'')";

您可以看到双"单"引号代替语​​言

you can see the "double" "single" quotes in place of languages