Select box multiple options with multiple where clause

Question

I have a select box that contains contractors and states. The user can select any number of contractors or states to search. How can I get the e-mail addresses using this multiple select box? My issue is that they could select multiple contractors, multiple states, or no states at all, etc....

How would I go about getting the e-mails under all of these conditions?

Select box:

<select name="CID[]" id="CID[]" class="chosen-select" multiple="multiple">
    <option value="All">All Active Contractors</option>
    <?php foreach ($cq as $row): ?>
    <option value="<?=$row['CID']?>"><?=$row['name']?></option>
    <?php endforeach; ?>
    <option value="AL">Alabama</option>
    <option value="AK">Alaska</option>
    <option value="AZ">Arizona</option>
    <option value="AR">Arkansas</option>
    <option value="CA">California</option>
    <option value="CO">Colorado</option>
    <option value="CT">Connecticut</option>
    <option value="DE">Delaware</option>
    <option value="FL">Florida</option>
    <option value="GA">Georgia</option>
    <option value="HI">Hawaii</option>
    <option value="ID">Idaho</option>
    <option value="IL">Illinois</option>
    <option value="IN">Indiana</option>
    <option value="IA">Iowa</option>
    <option value="KS">Kansas</option>
    <option value="KY">Kentucky</option>
    <option value="LA">Louisiana</option>
    <option value="ME">Maine</option>
    <option value="MD">Maryland</option>
    <option value="MA">Massachusetts</option>
    <option value="MI">Michigan</option>
    <option value="MN">Minnesota</option>
    <option value="MS">Mississippi</option>
    <option value="MO">Missouri</option>
    <option value="MT">Montana</option>
    <option value="NE">Nebraska</option>
    <option value="NV">Nevada</option>
    <option value="NH">New Hampshire</option>
    <option value="NJ">New Jersey</option>
    <option value="NM">New Mexico</option>
    <option value="NY">New York</option>
    <option value="NC">North Carolina</option>
    <option value="ND">North Dakota</option>
    <option value="OH">Ohio</option>
    <option value="OK">Oklahoma</option>
    <option value="OR">Oregon</option>
    <option value="PA">Pennsylvania</option>
    <option value="RI">Rhode Island</option>
    <option value="SC">South Carolina</option>
    <option value="SD">South Dakota</option>
    <option value="TN">Tennessee</option>
    <option value="TX">Texas</option>
    <option value="UT">Utah</option>
    <option value="VT">Vermont</option>
    <option value="VA">Virginia</option>
    <option value="WA">Washington</option>
    <option value="WV">West Virginia</option>
    <option value="WI">Wisconsin</option>
    <option value="WY">Wyoming</option>
    </select>

Query-ish:

$contractorquery = $db->prepare("SELECT CM.email, HO.name, HO.lastname, LL.state 
FROM tbl_ContactMethods AS CM
JOIN tbl_HomeOwner AS HO ON HO.HID = CM.HID
JOIN tbl_Locations AS LL ON LL.HID=HO.HID
JOIN tbl_PressControl AS PC ON PC.HID = HO.HID
WHERE PC.CID = ??????? AND LL.state = ??????  AND PC.active = 1 AND CM.email IS NOT NULL");
$contractorquery->execute();
$cq = $contractorquery->fetchAll();

I have the query to get everything if they select "All" because I just took out most of the where clauses:

SELECT CM.email, HO.name, HO.lastname 
FROM tbl_ContactMethods AS CM
JOIN tbl_HomeOwner AS HO ON HO.HID = CM.HID
JOIN tbl_PressControl AS PC ON PC.HID = HO.HID
WHERE PC.active = 1 AND CM.email IS NOT NULL

Answer 1

You must use IN('contratcor1','contractor2','and so ON')

$contractorquery = $db->prepare("SELECT CM.email, HO.name, HO.lastname, LL.state 
FROM tbl_ContactMethods AS CM
JOIN tbl_HomeOwner AS HO ON HO.HID = CM.HID
JOIN tbl_Locations AS LL ON LL.HID=HO.HID
JOIN tbl_PressControl AS PC ON PC.HID = HO.HID
WHERE PC.CID IN('contratcor1','contractor2','and so ON') AND LL.state = ??????  AND     
PC.active = 1 AND CM.email IS NOT NULL");