在PHP中变量前后插入不同的字符串

Question

I have 4 PHP variables, each variable consists of dynamic checkboxes, sometimes it can be one variable sometimes more but not more than 4:

$type = 'type_id = 2';
$color = 'color_id = 3';
$man = 'man_id = 5';
$size = 'size_id = 4 or size_id = 5';

I need to form of these variables Mysql query, the problem is how to add WHERE and AND strings before each variable. In front of first variable I need to add WHERE (it can be $type or $color or other). If first variable is active and other is checked I need to add AND to form proper query. e.g

if checked only "type" checkboxes:

WHERE $type

if checked "size" and "type" checkboxes:

WHERE $size AND $type

and so on... Hope you understand my problem, sorry for bad english.

Answer 1

$parts = array();
if (!empty($type)) {
    $parts[] = '(' . $type . ')';
}
if (!empty($color)) {
    $parts[] = '(' . $color . ')';
}
if (!empty($man)) {
    $parts[] = '(' . $man . ')';
}
if (!empty($size)) {
    $parts[] = '(' . $size. ')';
}
$where = '';
if (!empty($parts)) {
    $where = 'WHERE ' . implode(' AND ', $parts);
}
$select .= $where;