title: Included SQL fragment doesn't substitute parameter
body: <p>My mapper interface looks like this.</p>
  
  <pre class="lang-java prettyprint-override"><code>public interface CommonMapper {
      long selectSequenceNumber(String sequenceName);
  }
  </code></pre>
  
  <p>And I prepared sql mapper looks like this.</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;sql id="sequenceNumber"&gt;
    &lt;choose&gt;
      &lt;when test="_databaseId == 'derby'"&gt;
        VALUES NEXT VALUE FOR #{sequenceName}
      &lt;/when&gt;
      &lt;otherwise&gt;
        SELECT #{sequenceName}.NEXTVAL FROM DUAL
      &lt;/otherwise&gt;
    &lt;/choose&gt;
  &lt;/sql&gt;
  &lt;select id="selectSequenceNumber" resultType="_long"&gt;
    &lt;!--&lt;include refid="....mapper.CommonMapper.sequenceNumber"/&gt;--&gt;
    &lt;include refid="sequenceNumber"/&gt;
  &lt;/select&gt;
  </code></pre>
  
  <p>When I test mapper <code>#{sequenceName}</code> part is not substituted with given.</p>
  
  <pre><code>14:36:09.492 [main] DEBUG ....selectSequenceNumber - ==&gt;  Preparing: VALUES NEXT VALUE FOR ? 
  14:36:09.724 [main] ERROR ....PersistenceTests - failed to apply function for SqlSession
  org.apache.ibatis.exceptions.PersistenceException: 
  ### Error querying database.  Cause: java.sql.SQLSyntaxErrorException: Syntax error: Encountered "?" at line 1, column 23.
  ### The error may exist in .../CommonMapper.xml
  ### The error may involve ....CommonMapper.selectSequenceNumber
  ### The error occurred while executing a query
  ### SQL: VALUES NEXT VALUE FOR ?
  ### Cause: java.sql.SQLSyntaxErrorException: Syntax error: Encountered "?" at line 1, column 23.
  </code></pre>
  
  <p>Is this normal? How can I fix this?</p>