title: Get a range of keys with redis?
body: <p>Something that comes up all the time with our data set at work is needing to query for a bunch of values given a range of keys. Date ranges are an obvious example. </p>
  
  <p>I know you can use unix timestamps and a sorted set to query by date ranges, but it seems annoying, because I'd have to either </p>
  
  <ol>
  <li>put the whole document as the value in the sorted set, or </li>
  <li>just put ids in it, then ask redis for each key. </li>
  </ol>
  
  <p>Maybe option 2 is standard? Is there a way to ask redis for multiple keys at once? Like mongodb's $in query? Or perhaps asking for a bunch of keys in a pipeline is just as fast? </p>