title: How to select n% random rows with specific condition in SQL?
body: <p>I have two tables. </p>
  
  <p>Table1 has two columns: <code>brand</code> and <code>review_counter</code>. </p>
  
  <p>Table2 also has two columns: <code>brand</code> and <code>review</code>.</p>
  
  <p>There are several reviews for each brand. Is there any way in SQL to randomly select around 10% of reviews for each brand, without using "top n" command? </p>
  
  <p>For example for 'Sony' there are 2,005 reviews, and I need to select 10% of them, 200 reviews. </p>
  
  <p>Thank you in advance.</p>