如何计算相关表中的行数

Question

I have two tables in my database

articles With the following fields

id author post_date modification title section_id views featured content post_status

sections With the following fields

• sec_id description slug category

I have a function in my model to return all the sections

function get_all() {
            $q = $this->db->select('sec_id,category,slug,description')
                            ->from('sections')
                        ->order_by('category','asc');
            $ret['rows'] = $q->get()->result();
            return $ret;
        }

Am display this in a table

<div id="categories">

<div id="toolbar">
</div>

<table>
<thead class="table_header">
<tr>
<th><input type="checkbox" name="check_all" id="master_box" onclick="toggle(this)" /></th>
<?php foreach($fields as $field_name => $field_display):?>
<th><?php echo $field_display ?></th>
<?php endforeach; ?>
</tr>
</thead>

<tfoot class="table_header">
<tr>
<th><input type="checkbox" name="check_all" id="master_box" onclick="toggle(this)" /></th>
<?php foreach($fields as $field_name => $field_display):?>
<th><?php echo $field_display ?></th>
<?php endforeach; ?>
</tr>
</tfoot>

<tbody>
<?php foreach($categories as $cat):?>
<tr>
<td><input id="sec_id"name="id[]" type="checkbox" value="<?php echo $cat->sec_id; ?>" /></td>
<td><?php echo $cat->category; ?></td>
<td><?php echo $cat->description; ?></td>
<td><?php echo $cat->slug; ?></td>
<td></td>
</tr>
<?php endforeach;?>
</tbody>

</table>

</div>

If you notice there is an empty tag.It is meant to display the number of articles in the category(section).

How do get the number of articles associated with each category?

Answer 1

SELECT s.sec_id,s.category,s.slug,s.description,COUNT(a.id) FROM sections s 
    LEFT JOIN articale a ON s.sec_id = a.section_id 
WHERE 1 
GROUP BY s.sec_id 
ORDER BY s.category ASC