如何在PHP中进行下拉基础MySQL查询

Question

I have 6 <select> boxes. I am making a report base on <select> boxes. What I have done is make a form and and set method to GET and then getting these values through $_GET method on next page. Like

<form method="get" action="report.php">

<select name="select1">
<option value="none">Select value</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>


<select name="select2">
<option value="none">Select value</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>

<select name="select3">
<option value="none">Select value</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
.....................
</form>

Here is PHP code. (These are all sample data :P) Just trying to tell you people my problem. I am getting all values an check if it's value equal to none or not and do this, etc.

if(
$cby == "none" 
&& $crequirment == "none" 
&& $cdepartment == "none" 
&& $period == "none" 
&& $ccontact == "none" 
&& $cattend == "none"
)
{
    $query = mysqli_query($db, "SELECT * FROM customer");
}



else if (
$cby != "none" 
&& $crequirment == "none" 
&& $cdepartment == "none" 
&& $period == "none" 
&& $ccontact == "none" 
&& $cattend == "none"
)
{
    $query = mysqli_query($db, "SELECT * FROM customer WHERE cby = $cby");
}
else if (
$cby == "none" 
&& $crequirment == "none" 
&& $cdepartment != "none" 
&& $period == "none" 
&& $ccontact == "none" 
&& $cattend == "none")
{
    $query = mysqli_query($db, "SELECT * FROM customer WHERE cdepartment = $cdepartment");
}
else if..........

What I want is to make as simple as possible. What method should I have to adopt for it?

Answer 1

Optimize your code.

Create selects with names like data[cby], data[crequirment].
Instead of none use empty string.

In PHP:

if (isset($_GET['data']) {
    $where = [];

    foreach ($_GET['data'] as $name => $value) {
        if ($value != '') {
            $where[] = $name."=".$value; // sanitize `$name` and `$value` first
        }
    }

    if (!empty($where)) {
        $whereString = ' WHERE '.implode(' AND ', $where);
    } else {
        $whereString = '';
    }

    $query = mysqli_query($db, "SELECT * FROM customer".$whereString);
}