title: PHP SQL Column = Column minus $value
body: <p>I know how to add value  within the SQL Query
  So current value of Bank = Bank + Value</p>
  
  <pre><code>UPDATE users SET Bank=Bank + '$deposit' WHERE Username='".($_SESSION['username'])."'"
  </code></pre>
  
  <p>As Example if $deposit = '500' so string/text =  500
  and Example Bank value is 1000 it is 1500 right.
  Now i try to substract with current value.</p>
  
  <pre><code>UPDATE users SET Bank=Bank + '-500' WHERE Username='".($_SESSION['username'])."'"
  </code></pre>
  
  <p>Should be working.
  What not works is:</p>
  
  <pre><code>UPDATE users SET Bank=Bank + '-' + '$deposit' WHERE Username='".($_SESSION['username'])."'"
  </code></pre>
  
  <p>or</p>
  
  <pre><code>UPDATE users SET Bank=Bank + '-$deposit' WHERE Username='".($_SESSION['username'])."'"
  </code></pre>
  
  <p>What should i do?</p>
  
  <p>Alright i've sold it myself, thanks for everyone that tried to help, ya'll brought me on the idea of the answer : </p>
  
  <pre><code>UPDATE users SET Bank=Bank +- '$deposit' WHERE Username='".($_SESSION['username'])."'
  </code></pre>
  
  <p>instead of only using</p>
  
  <pre><code>-
  </code></pre>
  
  <p>ive used </p>
  
  <pre><code>+-
  </code></pre>
  
  <p>Thanks.</p>