php从mysql数据库进行查询得到错误，如'where子句'中的未知列[关闭]

I have this piece of code in php for make a query from mysql database

if(isset($_SESSION["esb2b_userid"])){
     $check_row = mysql_num_rows(mysql_query("select * from esb2b_basket where es_session='.$site.' and es_uid=".$_SESSION["esb2b_userid"]) or die(mysql_error()));

     echo "Logged in as <b>" . $_SESSION["esb2b_username"] . "</b>" ;
    ?> <?   }else{
    ?>  <? echo "$to" ?> Our Website <? } ?> <? if($_SESSION['esb2b_userid']=='')
            {?> <span id="log-info"><a href="<?=$domain_url?>/signup.html"><? echo "$Join_Free" ?></a><?php }?> |

     <? if($_SESSION['esb2b_userid']=='')
            {?> <a href="<?=$domain_url?>/signin.php?file="><? echo "$Sign_In" ?></a><?php } else { ?><a href="<?=$domain_url?>/logout.php" > <? echo "$Sign_out" ?> </a><?php }?>

But here I am getting error like this

Unknown column 'esb2b_userid' in 'where clause'

So can someone kindly tell me whay I am getting this result and how can I solve this issue? Any help and suggestions will be really appreciable. Thanks

change this

mysql_query("select * from esb2b_basket where es_session='.$site.' and es_uid=".$_SESSION["esb2b_userid"])

to

mysql_query("select * from esb2b_basket where es_session='".$site."' and es_uid=".$_SESSION["esb2b_userid"])

Your parentheses in your query are a bit mixed up, try:

$check_row = mysql_num_rows(mysql_query("select * from esb2b_basket where es_session='".$site."' and es_uid='".$_SESSION["esb2b_userid"]."') or die(mysql_error()));

you should escape your variable by mysql_real_escape_string from sql injection try this

  $check_row = mysql_num_rows(mysql_query("select * from esb2b_basket 
  where es_session= '".mysql_real_escape_string($site)."' 
         and es_uid='".mysql_real_escape_string($_SESSION["esb2b_userid"])."' ") or die(mysql_error()));

and please dont use mysql , change to mysqli or PDO