如何从SQL提取数据字段

Question

I am a hobbyist programmer and stuck with php and sql

I have a website where I hope to allow different users to list their domains and websites for sale. I have an SQL database with the fields: id , domain and price . Now I added a column of data where "namer" is the field name.

I am trying to extract the field "namer" so it appears on the website but it won't work.

The problem starts at // PROBLEM AREA in the code and after that div it's okay.

<div class="domain_list_item_main_linear" style="font-family: 'Open Sans', Arial; width:98%;">

    <div style="width:33%;float:left;">
        <a href="<?php /*?><?php echo ConfigPeer::GetValue('website_folder'); ?>
        <?php echo $domain->getCleanName(); ?><?php */?>https://www.afternic.com/domain/<?php echo urlencode($domain); ?>" class="moLPdomain" target="_blank">
        <?php echo html_entity_decode($domain->getDivTipNameLinear(), ENT_QUOTES); ?></a>

        <?php if(!$domain->getIsSold()): ?>
    </div>

    <div class="moLPprice" style="width:22%;float:left;margin-left:0px;">

        <?php 

        // PROBLEM AREA
            $eventid = $_GET['id'];
            $namer = $_GET['namer'];
            $result = mysql_query("SELECT $namer FROM `domain` WHERE `id` = '$eventid' ");
            $row = mysql_fetch_array($result);
            echo $row[$namer];      
        ?>  </div>

Answer 1

The problem is where you are using $namer .

The section after SELECT should contain the name of a column which contains the data you are trying to extract. Looking at your code, $namer isn't the name of the column, but some data that you are trying to match.

So the structure of the SQL should be like this:

SELECT column_name FROM table_name WHERE a_column_name = a_val;

I suggest you take a look at SQL SELECT statements, w3school's is a good place to start:

http://www.w3schools.com/php/php_mysql_select.asp

Edit:

You're SQL should look like this:

SELECT namer FROM domain WHERE id = $eventid;

If you want to get the 'namer' of the domain with that ID.

You're variable $namer must be storing any of the following words for your query to run:

id
domain
price