title: can we store negative (-) and plus (+) sign numbers in mysql varchar column
body: <p>I need to store numbers with plus or minus signs in a varchar column in mysql. 
  I am using php. </p>
  
  <p>+100 saves 100</p>
  
  <p>100+ the insert fails</p>
  
  <p>-100 its ok shows -100</p>
  
  <p>100- the insert fails</p>