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Merge pull request #763 from stevel032/github/761 

Partial fix of #761, corrected bad characters
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documentation/tdenginedocs-en/super-table/index.html
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@ -6,9 +6,9 @@
<p>Like a table, you can create, show, delete and describe STables. Most query operations on tables can be applied to STable too, including the aggregation and selector functions. For queries on a STable, if no tags filter, the operations are applied to all the tables created via this STable. If there is a tag filter, the operations are applied only to a subset of the tables which satisfy the tag filter conditions. It will be very convenient to use tags to put devices into different groups for aggregation.</p>
<a class='anchor' id='Create-a-STable'></a><h2>Create a STable</h2>
<p>Similiar to creating a standard table, syntax is: </p>
<pre><code class="mysql language-mysql">CREATE TABLE &lt;stable_name&gt; (&lt;field_name&gt; TIMESTAMP, field_name1 field_type,…) TAGS(tag_name tag_type, …)</code></pre>
<pre><code class="mysql language-mysql">CREATE TABLE &lt;stable_name&gt; (&lt;field_name&gt; TIMESTAMP, field_name1 field_type, ...) TAGS(tag_name tag_type, ...)</code></pre>
<p>New keyword "tags" is introduced, where tag_name is the tag name, and tag_type is the associated data type. </p>
<p>Note：</p>
<p>Note: </p>
<ol>
<li>The bytes of all tags together shall be less than 512 </li>
<li>Tag's data type can not be time stamp or nchar</li>
@ -30,12 +30,12 @@ tags (location binary(20), type int)</code></pre>
create table t4 using thermometer tags ('shanghai', 20);
create table t5 using thermometer tags ('new york', 10);</code></pre>
<a class='anchor' id='Aggregate-Tables-via-STable'></a><h2>Aggregate Tables via STable</h2>
<p>You can group a set of tables together by specifying the tags filter condition, then apply the aggregation operations. The result set can be grouped and ordered based on tag value. Syntax is：</p>
<pre><code class="mysql language-mysql">SELECT function&lt;field_name&gt;,…
<p>You can group a set of tables together by specifying the tags filter condition, then apply the aggregation operations. The result set can be grouped and ordered based on tag value. Syntax is:</p>
<pre><code class="mysql language-mysql">SELECT function&lt;field_name&gt;, ...
FROM &lt;stable_name&gt;
WHERE &lt;tag_name&gt; &lt;[=|&lt;=|&gt;=|&lt;&gt;] values..&gt; ([AND|OR] …)
WHERE &lt;tag_name&gt; &lt;[=|&lt;=|&gt;=|&lt;&gt;] values..&gt; ([AND|OR] ...
INTERVAL (&lt;time range&gt;)
GROUP BY &lt;tag_name&gt;, &lt;tag_name&gt;…
GROUP BY &lt;tag_name&gt;, &lt;tag_name&gt; ...
ORDER BY &lt;tag_name&gt; &lt;asc|desc&gt;
SLIMIT &lt;group_limit&gt;
SOFFSET &lt;group_offset&gt;
@ -75,9 +75,9 @@ INTERVAL(10M)</code></pre>
<pre><code class="mysql language-mysql">DROP TABLE &lt;stable_name&gt;</code></pre>
<p>To delete a STable, all the tables created via this STable shall be deleted first, otherwise, it will fail.</p>
<a class='anchor' id='List-the-Associated-Tables-of-a-STable'></a><h3>List the Associated Tables of a STable</h3>
<pre><code class="mysql language-mysql">SELECT TBNAME,[TAG_NAME,…] FROM &lt;stable_name&gt; WHERE &lt;tag_name&gt; &lt;[=|=&lt;|&gt;=|&lt;&gt;] values..&gt; ([AND|OR] …)</code></pre>
<pre><code class="mysql language-mysql">SELECT TBNAME,[TAG_NAME, ...] FROM &lt;stable_name&gt; WHERE &lt;tag_name&gt; &lt;[=|=&lt;|&gt;=|&lt;&gt;] values..&gt; ([AND|OR] ...)</code></pre>
<p>It will list all the tables which satisfy the tag filter conditions. The tables are all created from this specific STable. TBNAME is a new keyword introduced, it is the table name associated with the STable. </p>
<pre><code class="mysql language-mysql">SELECT COUNT(TBNAME) FROM &lt;stable_name&gt; WHERE &lt;tag_name&gt; &lt;[=|=&lt;|&gt;=|&lt;&gt;] values..&gt; ([AND|OR] …)</code></pre>
<pre><code class="mysql language-mysql">SELECT COUNT(TBNAME) FROM &lt;stable_name&gt; WHERE &lt;tag_name&gt; &lt;[=|=&lt;|&gt;=|&lt;&gt;] values..&gt; ([AND|OR] ...)</code></pre>
<p>The above SQL statement will list the number of tables in a STable, which satisfy the filter condition.</p>
<a class='anchor' id='Management-of-Tags'></a><h2>Management of Tags</h2>
<p>You can add, delete and change the tags for a STable, and you can change the tag value of a table. The SQL commands are listed below. </p>