title: MySQL problem in the sorting of column set as varchar(255)
body: <p>I've problem to order the field <code>sID_contents_p</code> set to <code>VARCHAR (255)</code> form the table <code>ttt</code> stored an a database <code>MySql version 8.0.17</code></p>
  <p>This is the result on <strong><a href="https://www.db-fiddle.com/f/p2riT5SPF35sfryWBN3zfz/0" rel="nofollow noreferrer">db-fiddle.com</a></strong>, which offers MySQL 8</p>
  <p>I need this return, for example when <code>sID_contents_p</code> contains 1</p>
  <pre><code>+----------------+-----+
  | sID_contents_p | sID |
  +----------------+-----+
  | 1.1            |   1 |
  | 1.2            |   2 |
  | 1.3            |   3 |
  | 1.4            |   4 |
  | 1.5            |   5 |
  | 1.6            |   6 |
  | 1.7            |   7 |
  | 1.8            |   8 |
  | 1.9            |   9 |
  | 1.10           |  10 |
  | 1.11           |  11 |
  | 1.12           |  12 |
  | 1.13           |  13 |
  | 1.14           |  14 |
  | 1.15           |  15 |
  | 1.16           |  16 |
  | 1.17           |  17 |
  | 1.18           |  18 |
  | 1.19           |  19 |
  | 1.20           |  89 |
  +----------------+-----+
  </code></pre>
  <p>I've tried this query but the return not what you want (<em>see above</em>)....</p>
  <pre><code>mysql&gt; SELECT
      sID_contents_p,
      sID
  FROM
      `ttt` WHERE SUBSTRING_INDEX(sID_contents_p,&quot;.&quot;,1) = 1
  ORDER BY
      sID_contents_p ASC;
  +----------------+-----+
  | sID_contents_p | sID |
  +----------------+-----+
  | 1.1            |   1 |
  | 1.10           |  10 |
  | 1.11           |  11 |
  | 1.12           |  12 |
  | 1.13           |  13 |
  | 1.14           |  14 |
  | 1.15           |  15 |
  | 1.16           |  16 |
  | 1.17           |  17 |
  | 1.18           |  18 |
  | 1.19           |  19 |
  | 1.2            |   2 |
  | 1.20           |  89 |
  | 1.3            |   3 |
  | 1.4            |   4 |
  | 1.5            |   5 |
  | 1.6            |   6 |
  | 1.7            |   7 |
  | 1.8            |   8 |
  | 1.9            |   9 |
  +----------------+-----+
  20 rows in set (0.03 sec)
  </code></pre>