如何正确检查位 0 和无返回结果之间的差异

Question

CREATE TABLE test (id SERIAL PRIMARY KEY, status BIT(1));上面创建了表$stmt = $db->prepare("SELECT status FROM test WHERE id = '1'");$stmt->execute();$status = $stmt->fetchColumn();上面的调用表if($status == false) {   // no record exists so lets INSERT a record  echo 'Inserted Record<br>';}if($status == '0') {  // Update record  echo 'Updated Record Instance 1<br>';}if ($status == '1') {  //update record  echo 'Updated Record Instance 2<br>';}当表中没有返回结果时，我得到输出Inserted RecordUpdated Record Instance 1同样，如果我插入一行INSERT INTO test (id, status) VALUES ('1', '0');我得到相同的结果Inserted RecordUpdated Record Instance 1那么如何正确检查位0和无返回结果之间的差异呢？

Answer 1

这会做

$stmt = $db-> prepare("SELECT status FROM test WHERE id = '1'");

$stmt -> execute();

$status = $stmt->fetch(PDO::FETCH_ASSOC);

if ($status === false) { 

  // no record exists so lets INSERT a record

  echo 'Inserted Record<br>';

} else if ($status["status"] == 0) {

  // Update record

  echo 'Updated Record Instance 1<br>';

} else if ($status["status"] == 1) {

  //update record

  echo 'Updated Record Instance 2<br>';

}