mysql update in and set code example

Example 1: update set mysql

UPDATE tableName SET anAttribute = 'Something' WHERE anOtherAttribute = 'SomethingElse'

//All 'SomethingElse' values will become 'Something'

Example 2: php mysql update all rows in table new values

$idresult = $conn->query("SELECT id FROM pictures");

while ($row = $idresult->fetch_assoc()){
   mysqli_query($conn, "UPDATE pictures SET UniqueKey = '$UniqueKey' WHERE id = " . $row['id'];
}