title: How to compute the sum of multiple columns in PostgreSQL
body: <p>I would like to know if there's a way to compute the sum of multiple columns in PostgreSQL. </p>
  
  <p>I have a table with more than 80 columns and I have to write a query that adds each value from each column.</p>
  
  <p>I tried with SUM(col1, col2, col3 etc) but it didn't work.</p>