title: Time slicing in Oracle/SQL
body: <p>I have a large-ish Oracle table containing rows representing units of work, with columns for start time and end time in addition to other meta-data.</p>
  
  <p>I need to generate usage graphs from this data, given some arbitrary filtering criteria and a reporting time period.  E.g., show me a graph of all of Alice's jobs for the 24-hour period starting last Tuesday at 7:00am.  Each DB row will stack vertically in the graph.</p>
  
  <p>I could do this in a high-level language by querying all potentially relevant rows, time slicing each one into 1-minute buckets, and graphing the result.  But is there an efficient way to do this time slicing in SQL?  Or is there an existing Oracle technology that does this?</p>
  
  <p>Thanks!</p>