<p dir="auto"><strong>Content:</strong> To support <code class="notranslate">Top(expression)</code> of SQLServer query SQL, the first step is to parse this grammar through Sharding-Parser.</p>
<p dir="auto"><strong>Difficulty Rating:</strong>  ★★★☆☆</p>
<p dir="auto"><strong>Requirements:</strong><br>
- Understand <code class="notranslate">g4 file</code> of <code class="notranslate">ANTLR</code><br>
- Understand <code class="notranslate">Visitor</code> mechanism of <code class="notranslate">ANTLR</code><br>
- Can modify <code class="notranslate">xml</code> file</p>
<h2 dir="auto">Bug Report</h2>
<p dir="auto"><strong>For English only</strong>, other languages will not accept.</p>
<p dir="auto">Before report a bug, make sure you have:</p>
<ul dir="auto">
<li>Searched open and closed <a href="https://github.com/apache/incubator-shardingsphere/issues">GitHub issues</a>.</li>
<li>Read documentation: <a href="https://shardingsphere.apache.org/document/current/en/overview" rel="nofollow">ShardingSphere Doc</a>.</li>
</ul>
<p dir="auto">Please pay attention on issues you submitted, because we maybe need more details.<br>
If no response <strong>more than 7 days</strong> and we cannot reproduce it on current information, we will <strong>close it</strong>.</p>
<p dir="auto">Please answer these questions before submitting your issue. Thanks!</p>
<h3 dir="auto">Which version of ShardingSphere did you use?</h3>
<p dir="auto">4.0.1</p>
<h3 dir="auto">Which project did you use? Sharding-JDBC or Sharding-Proxy?</h3>
<p dir="auto">Sharding-Proxy</p>
<h3 dir="auto">Expected behavior</h3>
<p dir="auto">be opened<br>
navicat version:<br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/35563513/78348983-7b93f780-75d5-11ea-9392-823203a51067.png"><img src="https://user-images.githubusercontent.com/35563513/78348983-7b93f780-75d5-11ea-9392-823203a51067.png" alt="image" style="max-width: 100%;"></a><br>
Testing is ok<br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/35563513/78349110-a8480f00-75d5-11ea-9409-899b34540ad0.png"><img src="https://user-images.githubusercontent.com/35563513/78349110-a8480f00-75d5-11ea-9409-899b34540ad0.png" alt="image" style="max-width: 100%;"></a><br>
IDEA database :<br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/35563513/78349218-d62d5380-75d5-11ea-98af-2f291f50c617.png"><img src="https://user-images.githubusercontent.com/35563513/78349218-d62d5380-75d5-11ea-98af-2f291f50c617.png" alt="image" style="max-width: 100%;"></a></p>
<p dir="auto"><a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/35563513/78348886-57381b00-75d5-11ea-8da4-6762a26eae70.png"><img src="https://user-images.githubusercontent.com/35563513/78348886-57381b00-75d5-11ea-8da4-6762a26eae70.png" alt="image" style="max-width: 100%;"></a><br>
But DBeaver 7.0.1 is ok<br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/35563513/78348947-6cad4500-75d5-11ea-9677-5acad292bab5.png"><img src="https://user-images.githubusercontent.com/35563513/78348947-6cad4500-75d5-11ea-9677-5acad292bab5.png" alt="image" style="max-width: 100%;"></a></p>
<h3 dir="auto">Actual behavior</h3>
<h3 dir="auto">Reason analyze (If you can)</h3>
<h3 dir="auto">Steps to reproduce the behavior, such as: SQL to execute, sharding rule configuration, when exception occur etc.</h3>
<h3 dir="auto">Example codes for reproduce this issue (such as a github link).</h3>