title: Oracle SQL Search for or find character by its ascii value
body: <p>My challenge is to find certain characters across multiple tables.</p>
  
  <p>At my work the DB is set up to keep all date values in columns named like this d_date, d_inserteby_id, d_valid_to etc. 
  But underscore is a reserved char in SQL right, so a straight forward like '%D_%' wont work.</p>
  
  <p>So when im looking for rows containing a reference to a date i have to be a bit more creative then '%D_%' </p>
  
  <p>I know i can:
  <code>
      select * from table t where Upper(T.column) like '%D_%' escape '\'
  </code></p>
  
  <p>But how to search for that d and underscore using its ascii value?</p>