title: Hive regexp_extract returning NULL
body: <p>Relatively new to the world of regular expressions so please bear with me.
  I am trying to use regexp_extract to pull out a certain subset of data within the string but it is returning me NULL for the regular expression I am currently trying to use.</p>
  
  <p>The requirement is as follows :-</p>
  
  <p>String --> test=<strong>1233</strong>]3212] --> Extract 1233</p>
  
  <p>String --> test=<strong>123355</strong> --> 123355</p>
  
  <p>The idea is to extract all data after test= upto either the first ] or the end of string.</p>
  
  <p>The regular expression I have as of now which I am attempting to use via Hive's regexp_extract is --> <code>test=(.*?)]|.*</code></p>
  
  <pre><code>select regexp_extract('test=1233]','test=(.*?)]|.*',1);
  --1233 (CORRECT)
  
  select regexp_extract('test=1233]323]','test=(.*?)]|.*',1);
  --1233 (CORRECT)
  
  select regexp_extract('test=1233323abc','test=(.*?)]|.*',1);
  --NULL (Should return 1233323abc)
  </code></pre>
  
  <p>Would appreciate your suggestions. I am halfway there at this point :(</p>