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gatewayworker連接mysql后該怎么判斷表中是否存在某條數據

sunkkkk

使用中發(fā)現，如果數據庫中查找到數據可以正常運行，沒有查找到符合條件的數據會直接報錯。
$result=$db->select('id')->from('collect_device')->where("unique_identification_number= $fromid ")->single();
echo $result;

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1個回答
li914

報什么錯誤提示？

  • sunkkkk 2022-03-31

    Press Ctrl-C to quit. Start success.
    1PDOException: SQL:SELECT id FROM collect_device WHERE unique_identification_number= user SQLSTATE[42S22]: Column not found: 1054 Unknown column 'user' in 'where clause' in C:\phpStudy\PHPTutorial\WWW\kaiwu\vendor\GatewayWorker-for-win\Applications\YourApp\Connection.php:1774
    Stack trace:

    0 C:\phpStudy\PHPTutorial\WWW\kaiwu\vendor\GatewayWorker-for-win\Applications\YourApp\Connection.php(1954): Workerman\MySQL\Connection->execute('SELECT id FROM ...', Array)

    1 C:\phpStudy\PHPTutorial\WWW\kaiwu\vendor\GatewayWorker-for-win\Applications\YourApp\Events.php(81): Workerman\MySQL\Connection->single()

    2 [internal function]: Events::onMessage('7f0000010b54000...', '{"type":"bind",...')

    3 C:\phpStudy\PHPTutorial\WWW\kaiwu\vendor\GatewayWorker-for-win\vendor\workerman\gateway-worker-for-win\src\BusinessWorker.php(384): call_user_func('Events::onMessa...', '7f0000010b54000...', '{"type":"bind",...')

    4 [internal function]: GatewayWorker\BusinessWorker->onGatewayMessage(Object(Workerman\Connection\AsyncTcpConnection), Array)

    5 C:\phpStudy\PHPTutorial\WWW\kaiwu\vendor\GatewayWorker-for-win\vendor\workerman\workerman-for-win\Connection\TcpConnection.php(629): call_user_func(Array, Object(Workerman\Connection\AsyncTcpConnection), Array)

    6 [internal function]: Workerman\Connection\TcpConnection->baseRead(Resource id #28)

    7 C:\phpStudy\PHPTutorial\WWW\kaiwu\vendor\GatewayWorker-for-win\vendor\workerman\workerman-for-win\Events\Select.php(286): call_user_func_array(Array, Array)

    8 C:\phpStudy\PHPTutorial\WWW\kaiwu\vendor\GatewayWorker-for-win\vendor\workerman\workerman-for-win\Worker.php(856): Workerman\Events\Select->loop()

    9 C:\phpStudy\PHPTutorial\WWW\kaiwu\vendor\GatewayWorker-for-win\vendor\workerman\gateway-worker-for-win\src\BusinessWorker.php(190): Workerman\Worker->run()

    10 C:\phpStudy\PHPTutorial\WWW\kaiwu\vendor\GatewayWorker-for-win\vendor\workerman\workerman-for-win\Worker.php(473): GatewayWorker\BusinessWorker->run()

    11 C:\phpStudy\PHPTutorial\WWW\kaiwu\vendor\GatewayWorker-for-win\vendor\workerman\workerman-for-win\Worker.php(382): Workerman\Worker::runAllWorkers()

    12 C:\phpStudy\PHPTutorial\WWW\kaiwu\vendor\GatewayWorker-for-win\Applications\YourApp\start_businessworker.php(35): Workerman\Worker::runAll()

    13 {main}

    process C:\phpStudy\PHPTutorial\WWW\kaiwu\vendor\GatewayWorker-for-win\Applications\YourApp\start_businessworker.php terminated and try to restart
    報了這一堆
  • li914 2022-03-31

    SELECT id FROM collect_device WHERE unique_identification_number= user 語句感覺有點奇怪 這個 user 是什么??？
    unique_identification_number 這個是int型字段string字段類型？
  • li914 2022-03-31

    報的錯誤是 collect_device 這個表中無 user 字段
  • sunkkkk 2022-03-31

    我要在表中查找unique_identification_number（varchar）的值為user的一條數據
  • li914 2022-03-31

    哥 加單引號才可以 不然數據庫會認為 user是字段名，不是 值
  • li914 2022-03-31

    $db->select('ID')->from('Persons')->where("sex= 'F' ")->single(); 例如這樣子
  • sunkkkk 2022-03-31

    getawayworker數據查詢查詢不到的時候會直接報錯嗎，我想知道我遇到的這個錯誤正不正常。有沒有辦法判斷表中是不是已經存在某條數據。謝謝了
  • li914 2022-03-31

    不會，你這是SQL語句錯誤
  • li914 2022-03-31 
      $result=$db->select('id')->from('collect_device')->where("unique_identification_number= '{$fromid}' ")->single();  這樣子寫語句，應該不會報錯了
  • li914 2022-03-31

    然后再根據查詢的結果判斷是否存在
  • sunkkkk 2022-03-31

    沒有報錯了，多謝。因為我在代碼里那個位置添的是$fromid，所以沒加''.我直到現在也不是很明白，我加的$fromid確實是個變量。按照你說的問題確實解決了，萬分感謝
  • 法師 2022-03-31

    這樣寫容易sql注入，最好按照手冊 bindValues 那樣傳參數
  • li914 2022-03-31

    $fromid 如果不加單引號，會直接認為是一個 字段名稱的
  • sunkkkk 2022-03-31

    明白了
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