<p>We’re given three tables representing a forum of users and their comments on posts.</p>

<p>We want to figure out if users are creating multiple accounts to upvote their own comments.</p>

<ol>
<li><p>What kind of metrics could we use to figure this out?</p></li>

<li><p>Write a query that could display the percentage of users on our forum that would be acting fraudulently in this manner. </p></li>
</ol>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>users</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>created_at</code></td>
<td>DATETIME</td>
</tr>

<tr>
<td><code>username</code></td>
<td>VARCHAR</td>
</tr>
</tbody>
</table>
<p><code>comments</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>created_at</code></td>
<td>DATETIME</td>
</tr>

<tr>
<td><code>post_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>user_id</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<p><code>comment_votes</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>created_at</code></td>
<td>DATETIME</td>
</tr>

<tr>
<td><code>user_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>comment_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>is_upvote</code></td>
<td>BOOLEAN</td>
</tr>
</tbody>
</table>


We want to figure out if users are creating multiple accounts to upvote their own comments.

Fraudulent Upvotes

Comments