php - If/else for INSERT query -

i running situation cannot figure out best way run if/else query. first, not sure if can run if/else sql statement. below have. through process, added if/else around query.

basically want run first query if equals $user_id otherwise, run else, want make value of user_id (database column - not variable listed above) equal $profile_viewer.

so, in nutshell, if can this, not sure how modify execute:

to include $profile_viewer parameter else query.

$select_img_stmt->execute(array($user_id));

    $user_id = ( isset( $_session['user'] ) ? $_session['user'] : "" );     $profile_viewer = $_get['user'];     if ($profile_viewer == $user_id) {         $img_select_sql = "             select *             profile_img             user_id = ?             order id desc             limit 1         ";     }     else {         //echo "this not image";         $img_select_sql = "         select *         profile_img             user_id = ?             order id desc             limit 1         ";     }     if ($select_img_stmt = $con->prepare($img_select_sql)) {         $select_img_stmt->execute(array($user_id)); 

updated code:

    $user_id = ( isset( $_session['user'] ) ? $_session['user'] : "" );     $profile_viewer = $_get['user'];     if ($profile_viewer == $user_id) {         /*$img_select_sql = "             select *             profile_img             user_id = ?             order id desc             limit 1         ";*/         $img_select_sql = "             select i.*             profile_img             user_id in (?, ?)             order id desc             limit 1;         ";     }     else {         //echo "this not image";         echo $profile_viewer;     }     if ($select_img_stmt = $con->prepare($img_select_sql)) {         $select_img_stmt->execute(array($user_id, $profile_viewer)); 

how doing in 1 query?

select i.* profile_img user_id in ($user_id, $profile_viewer) order (user_id = $user_id) desc limit 1; 

this has put variable values directly in code clarity. of course, recommend using parameters rather munging query string values.