title: INNER Join tables in sql
body: <p>I have two tables which I want to join together.</p>
  <p>TABLE_A:</p>
  <pre><code>+--------+-----------+---------+
  | row_id | category  | val_1   |
  +--------+-----------+---------+
  | 1      | cat1      | 6.5     |
  | 1      | test      | 6.5     |
  | 1      | dog1      | 2.1     |
  +--------+-----------+---------+
  </code></pre>
  <p>TABLE_B:</p>
  <pre><code>+-----------+-----------+
  | row_id    | val_2     |
  +-----------+-----------+
  | 1         | 2.0       |
  +-----------+-----------+
  </code></pre>
  <p>When I use INNER JOIN, get results like this:</p>
  <pre><code>+-----------+-----------+-----------+------------+
  | row_id    | category  | val_1     | val_2      |
  +-----------+-----------+-----------+------------+
  | 1         | cat1      | 6.5       | 2.0        |
  | 1         | test      | 6.5       | 2.0        |
  | 1         | dog1      | 2.1       | 2.0        |
  +-----------+-----------+-----------+------------+
  </code></pre>
  <p>But I do not want have duplicated result of Val_2. I want results like this:</p>
  <pre><code>+-----------+-----------+-----------+------------+
  | row_id    | category  | val_1     | val_2      |
  +-----------+-----------+-----------+------------+
  | 1         | cat1      | 6.5       | 2.0        |
  | 1         | test      | 6.5       | NULL       |
  | 1         | dog1      | 2.1       | NULL       |
  +-----------+-----------+-----------+------------+
  </code></pre>
  <p>I'd really appreciate it if someone could help me.</p>