跨多个字段的搜索查询，包括 JOIN

Question

Put simply, I want to run a search query on my database but i'm a little lost on how to appraoch it.

To start with, the search is not an open text field for the user to input anything they like, but is made up of three select menus of set fields and four checkboxes.

Select menu one is job catagories ('catagory_id'), which consists of numerous catagories PLUS an 'All Jobs' field for which there is no equiivilant database entry but which i thought would, if selected, return all jobs irrespective of catagory but dependent on the next two select fields (obviously). However, the catagory of each job (which is a required field and will always be completed) is stored using a Toxi solution as per the following database structure, because jobs can (and are encouraged) to include a number of catagories. From the first select menu then, i can assign each catagory value to be equal to the catagory id.

CREATE TABLE `jobinfo` (
`job_id` INT NOT NULL AUTO_INCREMENT, 
`company_name` VARCHAR(50) NOT NULL, 
`job_title` TEXT NOT NULL, 
`url` VARCHAR(255) NOT NULL,
'country'  VARCHAR(50) NOT NULL,
'state'  VARCHAR(50) NOT NULL,
'city'  VARCHAR(50) NOT NULL,
'job_type'  VARCHAR(50) NOT NULL,
PRIMARY KEY (`job_id`)
)

CREATE TABLE `categories` (
`category_id` INT NOT NULL AUTO_INCREMENT, 
`category_name` VARCHAR(20) NOT NULL, 
PRIMARY KEY (`category_id`)
)

CREATE TABLE `tag_relational` (
`job_id` INT NOT NULL, 
`category_id` INT NOT NULL
)

The second and third select fields are location based (country and state/county). These are a little simpler and are just stored in the main jobinfo table. But again, i want a general option so if a user selects USA as country, in the State select field, theres an option to view all jobs in the USA, or drill down by individual states, and obviously applying the same logic to other countries.

(For information, the third select field is populated client side dependent on the selection made in the second select menu - so if a user selects United Kingdom in the second field, the third is populated with the respective counties/areas.)

And finally, i have four checkboxes which relate to the job type - permenant, contract, freelance and telework. Again, these are mandatory selections and are stored in the main jobinfo table as strings.

So i want the query to return either all jobs or based on the chosen catagory, in particular geographic locations based on select menu two and three, OR ignoring select column three IF the visitor choose 'All States' or 'All Counties' etc. Also, if the visitor doesn't select any of the four checkboxes, i want to return all the jobs listed which match the criterea from the first three select fields.

My form looks something like this:

    <select name= "jobtype" id = "jc" title = "Hold down Ctrl to select">
            <option>JOB CATAGORY</option>
            <option value = "All Jobs">All Jobs</option>
            <option value = "1">Job Cat One</option>
            <option value = "2">Job Cat Two</option>
            <option value = "3">Job Cat Three</option>
            <option value = "4">Job Cat Four</option>
            <option value = "5">Job Cat Five</option>
            <option value = "6">Job Cat Six</option>

        </select>

        <select name="countries"  name = "country" onChange="updatecities(this.selectedIndex)">
            <option selected>REGION</option>
            <option value="usa">USA</option>
            <option value="canada">Canada</option>
            <option value="uk">United Kingdom</option>
            <option value="eu">European Union</option>
            <option value="rotw">Rest of the World</option>
        </select>

        <select name="cities">  <!--onClick="alert(this.options[this.options.selectedIndex].value)"-->
        </select>

    <ul>
    <li><input type = "checkbox" name = "cat[]" value = "Permanent"/></li><label>Permanent</label>
    <li><input type = "checkbox" name = "cat[]" value = "Cpntract"/></li><label>Contract</label>
    <li><input type = "checkbox" name = "cat[]" value = "Freelance"/></li><label>Freelance</label>
    <li><input type = "checkbox" name = "cat[]" value = "Telework"/></li><label>Telework</label>
    </ul>

    <input type="submit" value = "GO" />

I did have a query (below) for returning results based on catagory submitted through checkbox array, thanks to an earlier question on SO, but this was a little flawed because it matched catagory selections exactly (ie, if a job was listed in catagory 1 and 4, and you only searched for 1, it wouldn't return the result), plus i have now added location to the mix:

$query = 
"SELECT j.*
FROM jobinfo j
JOIN tag_relational r
ON j.job_id=r.job_id
JOIN tags t
ON t.tag_id=r.tag_id
WHERE t.tag_id = $cat ORDER BY job_id DESC";

I appreciate its a long one and i hope someone has the time to help.

Thanks as always, Dan

EDIT: Can i just place a several queries within if statements depending on what's selected? Something like: IF jobtype is not empty and country is not empty but city is empty, select matching job type for country, else...?

Answer 1

Your question isn't entirely clear** so I made the following assumptions:

Assumptions:

1. You know your Javascript. ie $_GET['cities'] will always contain a valid/legal city name. This answer is just PHP and MySql (just like the tags of the question).
2. When you say the checkboxes are mandatory I assumed you needed radio buttons.
3. When you talk about states you mean cities because there is no <select> for states.
4. The first <select> is for categories and the group of checkboxes radio buttons is for jobinfo.job_type

---

Code:

$legal_values['categories']=array(0=>'', 1=>'One', 2=>'Two', 3=>'Three', 4=>'Four', 5=>'Five', 6=>'Six');
$legal_values['countries']=array('usa'=> 'USA','canada'=>'Canada', 'uk'=>'United Kingdom', 
    'eu'=>'European Union', 'rotw'=>'Rest of the World');
$legal_values['term']=array(0 => 'Permanent', 1=> 'Contract', 2=>'Freelance', 3=>'Telework');

echo "<form action=\"{$_SERVER['PHP_SELF']}\" method=\"POST\">";
foreach($legal_values as $select_name => $legal_values)
{
    if($select_name=='term')
    {
        foreach($legal_values as $index => $val)
        {
            if(isset($_GET[$select_name]) && $_GET[$select_name]==$val)
            {
                $selected[$select_name]=$val;
                $isSelected=true;
            }
            else
            {
                $selected[$select_name]="";
                $isSelected=false;
            }
            echo "<label for=\"radio_{$index}\">{$val}</label>
            <input type=\"radio\" name=\"{$select_name}\" id=\"radio_{$index}\" value=\"{$val}\"" 
            .($isSelected?' selected="selected"':'').'>';
        }
    }
    else
    {
        $isCategories=$select_name=='categories'?true:false;
        echo '<select name="'.
            (($isCategories)?
            'jobtype" id = "jc" title = "Hold down Ctrl to select">
                <option>JOB CATAGORY'
            : 'countries" onChange="updatecities(this.selectedIndex)">
                <option>REGION')
            .'</option>';

        foreach($legal_values as $index => $val)
        {
            if(isset($_GET[$select_name]) && $_GET[$select_name]==$val)
            {
                $selected[$select_name]=$val;
                $isSelected=true;
            }
            else
            {
                $selected[$select_name]="";
                $isSelected=false;
            }
            echo "<option value = \"{$index}\" "
            .($isSelected?' selected="selected"':'')
            .">".($isCategories?'Job Cat':'')." {$val}</option>";
        }
        echo '</select>';

        echo '<select name="cities">  <!--onClick="alert(this.options[this.options.selectedIndex].value)"-->
        </select>';
    }
}
echo '<input type="submit" value = "GO" />
</form>';

$specific_cat=isset($selected['categories']) && $selected['categories']==0?true:false;
$specific_city=(isset($_GET['cities']) && $_GET['cities']==/*Whatever that first state option is for each country*/)?true:false;

$SQL_result = mysql_query('
SELECT DISTINCT jobinfo.* 
FROM jobinfo'
.($specific_cat?', categories, tag_relational ':'')
.'WHERE '.($specific_cat?"jobinfo.job_id=tag_relational.job_id
            AND tag_relational.category_id={$selected['categories']} AND ":'')
        .($specific_city?'jobinfo.city="'.mysql_real_escape_string($_GET['cities']).'" ':'')
."jobinfo.country=\"{$selected['countries']}\"
AND jobinfo.job_type=\"".mysql_real_escape_string($selected['term'])."\"
ORDER BY jobinfo.job_id DESC;");

//print table of jobs:
$NUM_jobs = mysql_num_rows($SQL_result);//courses to be displayed on this search results
$counter=0;
if($NUM_jobs>0)//if any courses match the search
{
    while($DB_ROW=mysql_fetch_assoc($SQL_result))//go through results by row
    {
        $counter++;
        if($counter==1)
        {
            echo '<table>
            <tr>
            <th>#</th>';
            foreach ($DB_ROW as $label => $val)
            {
                echo "<th>{$label}</th>";
            }
            echo '</tr>';
        }

        echo "<tr>
        <td>{$counter}</td>";
        foreach ($DB_ROW as $val)
        {
            echo "<td>{$val}</td>";
        }
        echo '</tr>';

        if($counter==$NUM_jobs)
        {
            echo '</table>';
        }
    }
    mysql_free_result($SQL_result);
}
//else: if nullset returned:
else{ echo '<p>Sorry, your search returned no results.</p>'; }

---

** Notes:

• One other thing, I'd suggest naming your <select> s and to suit your SQL. In your question you have a <select name="jobtype"> for categories and checkboxes called cat[] which are for the job type.
• Why is there two name attributes on the country <select> ?