使用mysqli_connect和mysql_select_db [英] use mysqli_connect and mysql_select_db

问题描述

此代码可以正常工作！

  $ con = mysqli_connect（localhost，root，，laboratory ）; 
 //检查连接
 if（mysqli_connect_errno（））
 {
 echo无法连接到MySQL：。 mysqli_connect_error（）; 
} 
 
 $ result = mysqli_query（$ con，SELECT * FROM test）; 
 
 while（$ row = mysqli_fetch_array（$ result））
 {
 echo $ row ['name']; 
 echo< br>; 
} 
 
 mysqli_close（$ con）;但是当我从mysqli_connect中删除database_name时，我将使用mysql_select_db，出现以下错误Warning：mysql_select_db（）;$ mysql_select_db （）期望参数2为资源，对象在
 
 
 
中给出。
  $ con = mysqli_connect（localhost，root，）; 
 //检查连接
 if（mysqli_connect_errno（））
 {
 echo无法连接到MySQL：。 mysqli_connect_error（）; 
} 
 
 $ db_selected = mysql_select_db（laboratory，$ con）; 
 
 if（！$ db_selected）
 {
 die（Can\'t use laboratory：。mysql_error（））; 
} 
 
 $ result = mysqli_query（$ con，SELECT * FROM test）; 
 
 while（$ row = mysqli_fetch_array（$ result））
 {
 echo $ row ['name']; 
 echo< br>; 
} 
 
 mysqli_close（$ con）; 
  
 
 
解决方案
请勿混用 mysqli 和 mysql ，因为它们是不同的模块。
 
 
 
你使用 mysql_select_db 和 mysql_error ，第一个需要 mysql 连接，而不是 mysqli 连接。
 
This code works correctly!
$con=mysqli_connect("localhost","root","","laboratory");
// Check connection
if (mysqli_connect_errno())
  {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
  }

$result = mysqli_query($con,"SELECT * FROM test");

while($row = mysqli_fetch_array($result))
  {
  echo $row['name'];
  echo "<br>";
  }

mysqli_close($con);
But when I remove database_name from mysqli_connect I would use the mysql_select_db, the following error occurs "Warning: mysql_select_db() expects parameter 2 to be resource, object given in"

Code after change:
$con=mysqli_connect("localhost","root","");
// Check connection
if (mysqli_connect_errno())
  {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
  }

$db_selected = mysql_select_db("laboratory", $con);

if (!$db_selected)
  {
  die ("Can\'t use laboratory : " . mysql_error());
  }

$result = mysqli_query($con,"SELECT * FROM test");

while($row = mysqli_fetch_array($result))
  {
  echo $row['name'];
  echo "<br>";
  }

mysqli_close($con);

解决方案
Please, don't mix mysqli and mysql as they are different modules.

In your second code block you are using mysql_select_db and mysql_error, the first one requires mysql connection, not mysqli connection.

                        
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