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Question

我正在使用直接標籤SQL在phpMyAdmin來執行我的查詢，但仍得到相同的錯誤Command out of sync error這裏嵌套奎雷斯同步錯誤的是我的MySQL查詢我試圖執行：

SELECT `courses`.`id`    as `courseId`, 
     `courses`.`Name`    as `courseName`, 
     `course2teacher`.`TeacherId` as `teacherId`, 
     (SELECT user.name 
     FROM user, 
       (SELECT course2teacher.TeacherId as tid 
       FROM course2teacher, 
         user, 
         follows, 
         teachers 
       WHERE user.id = 10 
         AND user.id = follows.studentid 
         AND course2teacher.id = follows.course2teacherid) as 
       teach 
     WHERE teach.tid = user.id) as teacherName, 
     `assignments`.`Assignment#` AS `assignmentName`, 
     `assignments`.`DueDate`  AS `duedate`, 
     `assignments`.`DueTime`  AS `duetime`, 
     `assignments`.`expiryDate` AS `expiryDate` 
FROM `teachers`, 
     `courses`, 
     `assignments`, 
     `course2teacher`, 
     `user`, 
     `follows` 
WHERE `user`.`id` = '10' 
     AND `user`.`id` = `follows`.`studentid` 
     AND `follows`.`course2teacherid` = `assignments`.`course2teacherId` 
     AND `course2teacher`.`id` = `follows`.`course2teacherid` 

這是我得到的錯誤消息：#2014 - Commands out of sync; you can't run this command now

爲什麼會出現這種情況，有什麼方法可以解決這個問題嗎？

Answer 1

ž

通常當一個結果集被打開，然後啓動另一個查詢之前未關閉時出現此錯誤。

我相信這會重新創建錯誤（爲了說明目的最小爲例）：

$CMySQL->query($VSQL); 

$RResult = $CMySQL->store_result(); 

$ARow = $RResult->fetch_assoc(); 

$CMySQL->query($VSQL); // error occurs here as result set is still open 

爲了解決這個問題下面的代碼可用於：

$CMySQL->query($VSQL); 

$RResult = $CMySQL->store_result(); 

$ARow = $RResult->fetch_assoc(); 

$RResult->free(); 

$CMySQL->next_result() 

$CMySQL->query($VSQL); // should work now 

總之我不認爲你的錯誤的原因是在查詢中，而不是你的代碼中發生的事情，並導致你的MySQL連接打開。要確定這是麥偉鋒提到的，你可以嘗試在獨立客戶端運行查詢，或者如果你想在代碼中執行查詢，請爲此查詢打開一個新連接，以查看錯誤是否再次出現。

問候，

詹姆斯