title: How to write specific raw query in typeorm querybuilder
body: <p>When I develop apps, I developed typeorm querybuilder for the aim of getting <code>attendance</code> data and <code>child</code> data.</p>
  <p>When I set following query builder.</p>
  <pre><code>const Result = await this.attendanceRepository
        .createQueryBuilder(&quot;attendance&quot;)
        .innerJoin(&quot;attendance.child&quot;, &quot;child&quot;)
        .select([&quot;attendance.childId&quot;,&quot;child.class&quot;,&quot;CONCAT(child.firstName,child.lastName) as'childName'&quot;])
        .where(&quot;attendance.id= :id&quot;, { id: id})
        .getOne()
        return Result;
  </code></pre>
  <p>I suffered following errors.</p>
  <p>It seems <code>child.lastName</code> is not defined.</p>
  <p>When I see the sql generated by querybuilder, the following is the cause of problem.</p>
  <pre><code>CONCAT(`child`.`first_name`,child.lastName) 
  </code></pre>
  <p>Are there any good way to resolve this ?</p>
  <p>Where should I fix ?</p>
  <pre><code> code: 'ER_BAD_FIELD_ERROR',
  api-server    |   errno: 1054,
  api-server    |   sqlMessage: &quot;Unknown column 'child.lastName' in 'field list'&quot;,
  api-server    |   sqlState: '42S22',
  api-server    |   index: 0,
  api-server    |   sql: &quot;SELECT `attendance`.`child_id` AS `attendance_child_id`, `attendance`.`id` AS `attendance_id`, `child`.`class` AS `child_class`, `child`.`id` AS `child_id`, CONCAT(`child`.`first_name`,child.lastName) as 'childName' FROM `attendances` `attendance` INNER JOIN `children` `child` ON `child`.`id`=`attendance`.`child_id` WHERE ( `attendance`.`id`= '5' ) AND ( `attendance`.`deleted_at` IS NULL )&quot;,
  api-server    |   query: &quot;SELECT `attendance`.`child_id` AS `attendance_child_id`, `attendance`.`id` AS `attendance_id`, `child`.`class` AS `child_class`, `child`.`id` AS `child_id`, CONCAT(`child`.`first_name`,child.lastName) as 'childName' FROM `attendances` `attendance` INNER JOIN `children` `child` ON `child`.`id`=`attendance`.`child_id` WHERE ( `attendance`.`id`= ? ) AND ( `attendance`.`deleted_at` IS NULL )&quot;,
  api-server    |   parameters: [ '5' ]
  </code></pre>
  <p>If someone has opinion, please let me know.</p>
  <p>Thanks</p>