title: Sql query performance difference between limit row count
body: <p>I have a hug table with 170,000 records.</p>
  <p>What is difference between this query</p>
  <pre><code>Showing rows 0 - 299 (1,422 total, Query took 1.9008 sec)
      SELECT 1 FROM `p_apartmentbuy` p 
      where 
      p.price between 500000000 and 900000000
      and p.yard = 1
      and p.dateadd between 1290000000 and 1320000000
      ORDER BY `p`.`id` desc
      limit 1669
  </code></pre>
  <p>Explain
  <img src="https://i.stack.imgur.com/qV6w3.png" alt="enter image description here" /></p>
  <p>And this one:</p>
  <pre><code>Showing rows 0 - 299 (1,422 total, Query took 0.2625 sec)
      SELECT 1 FROM `p_apartmentbuy` p 
      where 
      p.price between 500000000 and 900000000
      and p.yard = 1
      and p.dateadd between 1290000000 and 1320000000
      ORDER BY `p`.`id` desc
      limit 1670
  </code></pre>
  <p>Explain:
  <img src="https://i.stack.imgur.com/ZqRjT.png" alt="enter image description here" /></p>
  <p>Both of these queries are using 1 table with same data and have same where clasue, but only limit row count are different</p>