Question

I’m sure this is an easy question.

If you want to produce SQL with php for a search query. So you have say 5 criteria which are all optional and may or may not be inputted by the user. You cannot guarantee any of them.

When it comes to making the SQL in php you can use :

So if they exist then you can use AND for the 4 last criteria.

But for the first criteria if you have that as a WHERE if that one is not selected then the SQL just is a list of ANDs with no starting WHERE.

Is there an easy answer?

Code I’ve Written :

$sql = "
SELECT *
FROM Request, Rooms
WHERE Day = ".$Day." ";

if($ModCode != ''){
$sql .="AND ModCode = ".$ModCode." ";
}
if($StartTime != ''){
$sql .="AND StartTime = ".$StartTime." ";
}
if($Length != ''){
$sql .="AND Length = ".$Length." ";
}
if($Room != ''){
$sql .="AND Request.RoomID = Rooms.RoomID ";
$sql .='AND Rooms.RoomName = "'.$Room.'" ';
}
if($Room == '' && $Park != ''){
$sql .="AND Request.RoomID = Rooms.RoomID ";
$sql .='AND Rooms.Park = "'.$Park.'" ';
}

And now I want the bit WHERE Day = $Day to be optional like the others.

Cheers

Answer 1

You could store all criterias in an array and then implode AND between them:

if(!empty($array)) {
   $where_part = "WHERE " . implode(" AND ", $array);
}

Update:

$cond = array();

if($ModCode != ''){
$cond[] = "ModCode = ".$ModCode;
}
if($StartTime != ''){
$cond[] = "StartTime = ".$StartTime;
}
if($Length != ''){
$cond[] = "Length = ".$Length;
}
if($Room != ''){
$cond[] = "Request.RoomID = Rooms.RoomID";
$cond[] = 'Rooms.RoomName = "'.$Room.'"';
}
if($Room == '' && $Park != ''){
$cond[] = "Request.RoomID = Rooms.RoomID";
$cond[] = 'Rooms.Park = "'.$Park.'"';
}

if(!empty($cond)) {
    sql .= "WHERE " . implode(" AND ", $cond);
}