php - Mysqli_query works in one part of if-elseif statement, but not the other -

i working on event list page class taking. 1 of first time have worked php.

i want display filtered list of events depending on category chosen drop down list. want display complete list of events if 'all events' chosen ddl. have if-elseif statement change sql query depending on category value query string.

the specific error seeing list of events missing when 'all events' selected. echo statement of if-else work, , displaying correct values $category, $month, , $year. missing table containing list of events.

note: have tested query , have confirmed work pull list of events. have tried empty $category value no change.

this if statement work:

if(!empty($category)){  $catresult = mysqli_query($con," select cal_events.event_id,      cal_events.title,      date_format(cal_dates.date, '%m %d %y') formatted_date,      monthname('$month') nameofmonth     cal_events  left join cal_dates  on cal_events.event_id = cal_dates.event  cal_events.categories = '$category'  , year(date) = '$year'  , month(date) = '$month'  group cal_dates.date, cal_events.title, cal_events.event_id");  echo "<h2>$category</h2> <h3>events $monthname, $year</h3> <br /><br /> <table align='center'> <tr> <th>date</th> <th>event</th> <th></th> </tr>";  } 

this elseif statement not work:

elseif($category=='all'){       $catresult = mysqli_query($con," select cal_events.event_id,      cal_events.title,      date_format(cal_dates.date, '%m %d %y') formatted_date,      monthname('$month') nameofmonth cal_events  left join cal_dates  on cal_events.event_id = cal_dates.event  year(date) = '$year'  , month(date) = '$month'  group cal_dates.date, cal_events.title, cal_events.event_id");  echo "<h2>$category</h2> <h3>events $monthname, $year</h3> <br /><br /> <table align='center'> <tr> <th>date</th> <th>event</th> <th></th> </tr>";  } 

this while loop displaying list of events:

//displays list of events while($row = mysqli_fetch_array($catresult)) { echo "<tr>"; echo "<td>" . $row['formatted_date'] . "</td>"; echo "<td><a href='detail.php?id=".$row['event_id']."' target='_blank'>" .  $row['title'] . "</a></td>"; echo "</tr>"; } echo "</table>"; 

your if/elseif logic isn't mutually exclusive:

if(!empty($category)){   //... } elseif($category=='all'){   //... } 

if $category value 'all' first if block still execute. under no conditions elseif block ever execute.

you switch around conditions, or add additional check first one. like:

if(!empty($category) && $category!='all'){ 

but point if , elseif blocks have different subsets of total set of possibilities. if first block executes, second block definition won't.