For empty value set to zero in MySQL
<p>I try to set empty MySQL value to zero. I used IFNULL but it doesn't work. Sorry for my bad english. </p>

<pre><code>&lt;select name="stock_i_h_id" id="stock_i_h_id" class="form-control  m-bot15" required&gt;
&lt;option value="" selected="selected"&gt;--Select Item --&lt;/option&gt;
&lt;?php 
$ids=array();
$qry = mysql_query("SELECT IFNULL(stock_i_h_id,0) FROM other_stock_item_creation where userId='".$_SESSION['userId']."' and status_my='0'");
while($row_sid =  mysql_fetch_assoc($qry)){
    $ids[]=$row_sid["stock_i_h_id"]; 
}
$st = implode(",",$ids);                    
$ids2=array();
$qry2 = mysql_query("SELECT IFNULL(stock_i_h_id,0) FROM dpr_stock_item where userId='".$_SESSION['userId']."' and status_my='0'");
while($row_sid2 =  mysql_fetch_assoc($qry2)){
    $ids2[]=$row_sid2["stock_i_h_id"]; 
}
$st2 = implode(",",$ids2);

$stock_item_head_name = mysql_query("select * from stock_item_head_name where userId='".$_SESSION['userId']."' and status_my='0' and id not in (".$st.",".$st2.") order by id ASC"); 
$current_date= date('d-m-Y');
while($rows_stock_item_head_name = mysql_fetch_assoc($stock_item_head_name)) 
{
?&gt;
&lt;option value="&lt;?php echo $rows_stock_item_head_name['id'] ?&gt;"&gt;&lt;?php echo $rows_stock_item_head_name['stock_item_name'] ?&gt;&lt;/option required&gt;
&lt;?php 
}
?&gt;
</code></pre>

<p>If <code>$qry</code> and <code>$qry2</code> returns empty value then both $st and $st2 becomes empty and then I get <code>NOT IN('','')</code> instead <code>NOT IN(0,0)</code> in the third query(<code>$stock_item_head_name</code>)</p>

<p>Edit:
My code works fine without <code>IFNULL</code> when both the tables <code>other_stock_item_creation</code> and <code>dpr_stock_item</code> have entries. But when the tables are empty it's not working with <code>IFNULL</code> or <code>IF(stock_i_h_id = '', 0, stock_i_hd)</code></p>