title: ERROR 1054 (42S22): Unknown column '' in 'where clause'
body: <p>The MySQL query got following error.</p>
  
  <blockquote>
    <p>ERROR 1054 (42S22): Unknown column 'scope.full_name' in 'where clause'</p>
  </blockquote>
  
  <p>Here are two tables as below.</p>
  
  <p>1.scope:</p>
  
  <pre><code> +-----------+----------+-------------+--------------+------+----------+--------------+
      | handle_id | model_id | define_name | full_name    | name | file     | parent_scope |
      +-----------+----------+-------------+--------------+------+----------+--------------+
      |  15859248 |        0 | tb          | tb           | tb   | 12755864 |            0 |
      |  15859360 |        0 | RCA         | tb.RCA       | RCA  | 12755864 |     15859248 |
      |  15859472 |        0 | FA          | tb.RCA.x1    | x1   | 12755864 |     15859360 |
      |  15859584 |        0 | HA          | tb.RCA.x1.x1 | x1   | 12755864 |     15859472 |
      |  15859696 |        0 | HA          | tb.RCA.x1.x2 | x2   | 12755864 |     15859472 |
      |  15859808 |        0 | FA          | tb.RCA.x2    | x2   | 12755864 |     15859360 |
      |  15859920 |        0 | HA          | tb.RCA.x2.x1 | x1   | 12755864 |     15859808 |
      |  15860032 |        0 | HA          | tb.RCA.x2.x2 | x2   | 12755864 |     15859808 |
      |  15860144 |        0 | FA          | tb.RCA.x3    | x3   | 12755864 |     15859360 |
      |  15860256 |        0 | HA          | tb.RCA.x3.x1 | x1   | 12755864 |     15860144 |
      |  15860368 |        0 | HA          | tb.RCA.x3.x2 | x2   | 12755864 |     15860144 |
      |  15860480 |        0 | FA          | tb.RCA.x4    | x4   | 12755864 |     15859360 |
      |  15860592 |        0 | HA          | tb.RCA.x4.x1 | x1   | 12755864 |     15860480 |
      |  15860704 |        0 | HA          | tb.RCA.x4.x2 | x2   | 12755864 |     15860480 |
      +-----------+----------+-------------+--------------+------+----------+--------------+
  </code></pre>
  
  <p>2.file:</p>
  
  <pre><code>+-----------+----------+----------+----------+-------------------------------------------------------------------+------------+
  | handle_id | model_id | max_time | min_time | name                                                              | scale_unit |
  +-----------+----------+----------+----------+-------------------------------------------------------------------+------------+
  |  12755864 |        0 |    10000 |        0 | /directory/ART.txt                                               | 1ns        |
  +-----------+----------+----------+----------+-------------------------------------------------------------------+------------+
  </code></pre>
  
  <p>Query command is:</p>
  
  <pre><code>SELECT `name` FROM `file` WHERE `scope`.`full_name`='tb.RCA';
  </code></pre>
  
  <p>I understand backticks in MySQL means " allow spaces and other special characters (except for backticks, obviously) in table/column names", but even the following command causes same error.</p>
  
  <pre><code> SELECT name FROM file WHERE scope.full_name='tb.RCA';
  </code></pre>
  
  <p>For more information, MySQL server version is <strong>5.7.20</strong> on Linux system.</p>