title: How to remove duplicates on specific columns?
body: <p>I have a table like this:</p>
  <pre><code>// users
  +----+----------+-------+---------------------+
  | id |   name   |  age  | some other cols ..  |
  +----+----------+-------+---------------------+
  | 1  | Ali      | 15    | ..                  |
  | 2  | John     | 15    | ..                  |
  | 3  | Ali      | 22    | ..                  |
  | 4  | Martin   | 18    | ..                  |
  | 5  | Ali      | 15    | ..                  |
  | 6  | John     | 30    | ..                  |
  | 7  | John     | 15    | ..                  |
  +----+----------+-------+---------------------+
  </code></pre>
  <p>I want to add a <strong>composite</strong> unique index on <code>name, age</code> columns. Currently, it gives me <code>there are duplicates rows</code> error. Already, I was using <code>INSERT IGNORE ..</code> to do this job but sadly <code>IGNORE</code> is no longer supported in MySQL.</p>
  <p>Anyway, any idea how can I remove rows that have the same values on both <code>name</code> and <code>age</code> columns <strong>and keep just one of them (one of rows)</strong>? In other words, I want to remove all rows that have the same value on <code>name</code> and <code>age</code> columns except one of them.</p>
  <p>So, here is <strong>the expected result:</strong></p>
  <pre><code>// users
  +----+----------+-------+---------------------+
  | id |   name   |  age  | some other cols ..  |
  +----+----------+-------+---------------------+
  | 1  | Ali      | 15    | ..                  |
  | 2  | John     | 15    | ..                  |
  | 3  | Ali      | 22    | ..                  |
  | 4  | Martin   | 18    | ..                  |
  | 6  | John     | 30    | ..                  |
  +----+----------+-------+---------------------+
  </code></pre>
  <p>Any idea how can I do that?</p>