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/* Changing the layout to use less space for mobiles */
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                                    <a class="user-hover" rel="mauromol" id="email_mauromol" href="https://hibernate.onjira.com/secure/ViewProfile.jspa?name=mauromol" style="color:#6c797f;">Mauro Molinari</a>
     created <img src="https://hibernate.onjira.com/images/icons/bug.gif" height="16" width="16" border="0" align="absmiddle" alt="Bug"> <a style='color:#6c797f;text-decoration:none;' href='https://hibernate.onjira.com/browse/HHH-7735'>HHH-7735</a>
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                <a style='color:#6c797f;text-decoration:none;' href='https://hibernate.onjira.com/browse/HHH-7735'><strong>Subclass entity in a join produces wrong SQL query</strong></a>
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        <strong style="font-weight:normal;color:#505050;">Issue Type:</strong>
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                <img src="https://hibernate.onjira.com/images/icons/bug.gif" height="16" width="16" border="0" align="absmiddle" alt="Bug">        Bug
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        <strong style="font-weight:normal;color:#505050;">Affects Versions:</strong>
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                    3.6.10            </td>
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        <strong style="font-weight:normal;color:#505050;">Assignee:</strong>
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                    Unassigned            </td>
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        <strong style="font-weight:normal;color:#505050;">Components:</strong>
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                    query-hql            </td>
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        <strong style="font-weight:normal;color:#505050;">Created:</strong>
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        30/Oct/12 3:43 AM
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        <strong style="font-weight:normal;color:#505050;">Description:</strong>
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        <p style='margin-top:0;margin-bottom:10px;'>Consider the following entities:</p>

<p style='margin-top:0;margin-bottom:10px;'>Post</p>

<p style='margin-top:0;margin-bottom:10px;'>Comment (abstract)</p>
<table class='confluenceTable'><tbody>
<tr>
<td class='confluenceTd'>-&gt;PostComment (extends Comment, models a comment to a post)</td>
</tr>
</tbody></table>

<p style='margin-top:0;margin-bottom:10px;'>PostComment has a foreign key to Post: PostComment.post =&gt; Post.id<br/>
Comment has a discriminator column called commentType: discriminator value for PostComment is 'PC'.</p>

<p style='margin-top:0;margin-bottom:10px;'>Then, consider a join between PostComment and Post: the problem is most evident with a right join:</p>

<div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent">
<pre>select post.id, comment.id from PostComment as comment right join comment.post as post
</pre>
</div></div>

<p style='margin-top:0;margin-bottom:10px;'>This should show all the possible tuples (postid-commentid). For posts without comments, I expect to see tuples like (postid-null). However, the produced SQL looks like:</p>

<div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent">
<pre>select post1_.Id as col_0_0_, postcommen0_.Id as col_1_0_ 
 from CommentTable postcommen0_ right outer join PostTable post1_ on postcommen0_.postId=post1_.Id 
 where postcommen0_.CommentType='NW'
</pre>
</div></div>

<p style='margin-top:0;margin-bottom:10px;'>However, this is not the intended behaviour and this will produce as a result only tuples where comment.id is not null. This is because the "where" clause is filtering out all the rows where the CommentTable columns are null, invalidating the use of the right join.</p>

<p style='margin-top:0;margin-bottom:10px;'>The correct query that should be produced is:</p>

<div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent">
<pre>select post1_.Id as col_0_0_, postcommen0_.Id as col_1_0_ 
 from CommentTable postcommen0_ right outer join PostTable post1_ on postcommen0_.postId=post1_.Id, postcommen0_.CommentType='NW'
</pre>
</div></div>

<p style='margin-top:0;margin-bottom:10px;'>That is, the condition to match the subclass entity should be added to the join conditions, not to the "where" clause, so that they are applied before joining.</p>
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        <strong style="font-weight:normal;color:#505050;">Project:</strong>
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        <a style="color:#6c797f;" href="https://hibernate.onjira.com/browse/HHH">Hibernate ORM</a>
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        <strong style="font-weight:normal;color:#505050;">Priority:</strong>
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                <img src="https://hibernate.onjira.com/images/icons/priority_major.gif" height="16" width="16" border="0" align="absmiddle" alt="Major">        Major
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        <strong style="font-weight:normal;color:#505050;">Reporter:</strong>
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    <td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
                                        <a class="user-hover" rel="mauromol" id="email_mauromol" href="https://hibernate.onjira.com/secure/ViewProfile.jspa?name=mauromol" style="color:#6c797f;">Mauro Molinari</a>
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