PHP-PDO，如何返回select語句中的行數

Question

我有一個簡單的語句，但似乎無法從select語句中獲取行數，當它真的很簡單時真的讓我感到困擾。我不斷得到空串。

下面是代碼

include "connect.php"; 

$userID = $_POST['userID']; 
$threadID = $_POST['threadID']; 

$sql1 = "select * from AT_AddThread where AT_ID = :threadID"; 
$stmt = $conn->prepare($sql1); 
$stmt->execute(array(':threadID' => $threadID)); 
$result = $stmt->fetchColumn(7); 
//echo $result; 

$sql2 = "select * from TJ_ThreadJoined where TJ_T_ID = :threadID" 
$q2 = $conn->prepare($sql2); 
$q2->execute(array(':threadID' => $threadID)); 
$q2->execute(); 
$rows = $q2->fetchColumn(); 
echo $rows; //THIS IS where i want to return the number of rows from the select statement 

Answer 1

除了fetchColumn你可以嘗試以下方法：

1. 計算行數

   $rows = $stmt->fetchAll(); echo "count = " . count($rows);

2. 使用rowCount()

   echo "count = " . $stmt->rowCount();

3. 將它添加到查詢：在最後的查詢返回

   SELECT COUNT(*) as rowCount ...

   echo $row['rowCount'];

Answer 2

試試這個：

echo $q2->rowCount();

或

$row = $q2->fetch(PDO::FETCH_NUM); 
echo $row[0]; 

。

->rowCount();doc

Answer 3

你總是可以得到的行數。剛過SELECT聲明

$sql2 = "select SQL_CALC_FOUND_ROWS * from TJ_ThreadJoined where TJ_T_ID = :threadID" 

然後執行查詢SELECT FOUND_ROWS()添加SQL_CALC_FOUND_ROWS，抓取行，你將有行數從去年的查詢。