multiple columns in where clause query mysql

问题

selectbox with multiple columns from mysql database

The following code was the winning code from zgr024

       <?php 
    include '../config.php';
    $sql = "SELECT * FROM megabase";  
    $resultaat = mysql_query($sql) or die (mysql_error());  
    $domains = array();
    while ($row = mysql_fetch_array($resultaat))       
    { 
       if (!empty($row['domeinnaam1'])) $domains[] = $row['domeinnaam1'];
       if (!empty($row['domeinnaam2'])) $domains[] = $row['domeinnaam2'];
    }
?>

   <select size="1" name="domeinnaam">
<?php
    foreach ($domains as $domain)
    {
        echo "<option>$domain</option>";
    } 
?>
    </select>

But this code resulted in an expected error on the next page where i have the following code.

    <?php 

     //MySQL Database Connect
     include 'config.php';

    $domeinnaam=$_POST['domeinnaam']; 

    $data = 'SELECT * FROM megabase WHERE domeinnaam = "'.$domeinnaam.'"'; 
      $query = mysql_query($data) or die("Couldn't execute query. ". mysql_error()); 
      $data2 = mysql_fetch_array($query); 


    ?>

How do i change the last code to work with the first code:

I have tried:

        <?php 

         //MySQL Database Connect
         include 'config.php';

        $domeinnaam=$_POST['domeinnaam'];
       $domeinnaamquerry='domeinnaam1'.'domeinnaam2'.'domeinnaam3'.'domeinnaam4'.'domeinnaam5'.'do meinnaam6'.'domeinnaam7'.'domeinnaam8'.'domeinnaam9'.'domeinnaam10';

        $data = 'SELECT * FROM megabase WHERE $domeinnaamquerry = "'.$domeinnaam.'"'; 
          $query = mysql_query($data) or die("Couldn't execute query. ".             mysql_error()); 
          $data2 = mysql_fetch_array($query); 


        ?>

But i receive the following error: Couldn't execute query. Unknown column '$domeinnaamquerry' in 'where clause'

Okey got it working now it is sloppy but working thanks everyone for your input it was helpful. and thanks for the warnings.

here is the code

     <?php 

      //MySQL Database Connect
      include 'config.php';

     $domeinnaam=$_POST['domeinnaam']; 

     $data = 'SELECT * FROM megabase WHERE domeinnaam1="'.$domeinnaam.'" OR domeinnaam2="'.$domeinnaam.'" OR domeinnaam3="'.$domeinnaam.'" OR domeinnaam4="'.$domeinnaam.'" OR domeinnaam5="'.$domeinnaam.'" OR domeinnaam6="'.$domeinnaam.'" OR domeinnaam7="'.$domeinnaam.'" OR domeinnaam8="'.$domeinnaam.'" OR domeinnaam9="'.$domeinnaam.'" OR domeinnaam10="'.$domeinnaam.'"    '; 
       $query = mysql_query($data) or die("Couldn't execute query. ". mysql_error()); 
       $data2 = mysql_fetch_array($query); 


     ?>

回答1:

Try

<?php 

    //MySQL Database Connect
    include 'config.php';

    $domeinnaam=$_POST['domeinnaam']; 

    $data = "SELECT * FROM megabase WHERE domeinnaam1 = '$domeinnaam' OR domeinnaam2 = '$domeinnaam' "; 
    $query = mysql_query($data) or die("Couldn't execute query. ". mysql_error()); 
    $data2 = mysql_fetch_array($query); 

?>

回答2:

If you want a variable to be interpreted as its value in PHP, you can't use single quotes.

$foo = 'World';

echo 'Hello $foo'; // Hello $foo
echo "Hello $foo"; // Hello World

Thus, you want

$data = "SELECT * FROM megabase WHERE $domeinnaamquerry = '".$domeinnaam."'";

Although read this and this to understand why you REALLY don't want that.

来源：https://stackoverflow.com/questions/15205771/multiple-columns-in-where-clause-query-mysql

标签

php

mysql

where-clause

multiple-columns