Insert Code
$tid = $_POST['tid'];


// please remove last ' , (coma)' from fileds

mysqli_query($conn,"INSERT INTO `Baz` ( `tid`, ) VALUES ('$tid',)");
Select Single
$getdata = mysqli_query($conn,"SELECT * FROM Baz ");
$row = mysqli_fetch_array($getdata);
$tid = $row['tid'];
Select While
$getdata = mysqli_query($conn,"SELECT * FROM Baz ");
while($row = mysqli_fetch_array($getdata)) {
$tid = $row['tid'];
}
Delete Code
$getid = $_GET['id'];
mysqli_query($conn,"DELETE FROM Baz WHERE tid ='$id' ");
Update Single Code
$tid = $_POST['tid'];

mysqli_query($conn,"UPDATE `Baz` SET `tid` = '$tid' WHERE `Baz`.`tid` = 1")