1UPDATE tableName SET columnName = yourValue;
2#to update multiple columns:
3UPDATE tableName SET column1 = value1, column2 = value2; #and so on
1$idresult = $conn->query("SELECT id FROM pictures");
2
3while ($row = $idresult->fetch_assoc()){
4 mysqli_query($conn, "UPDATE pictures SET UniqueKey = '$UniqueKey' WHERE id = " . $row['id'];
5}