title: BQ giving incomplete results using CONTAINS condition
body: <p>I'm working with Bigquery to process some Adwords data and, more precisely, to extract all the url parameters from our destination URLs so we can organize it better and etc.</p>
  
  <p>I wrote the following Query to give me back all the parameters available in the "DestinationURL" field in the table. As follows:</p>
  
  <pre><code>SELECT Parameter
    FROM (SELECT NTH(1, SPLIT(Params,'=')) as Parameter,
          FROM (SELECT 
                AdID,
                NTH(1, SPLIT(DestinationURL,'?')) as baseurl,
                split(NTH(2, SPLIT(DestinationURL,'?')),'&amp;') as Params
                FROM [adwords_accounts_ads.ads_all] 
                HAVING Params CONTAINS '='))
  
   GROUP BY 1
  </code></pre>
  
  <p>Runnig this will give me 6 parameters. That is correct but incomplete, because in this testing table I know there are 2 other parameters in the URLs that were not fetched. One called 'group' and the other called 'utm_content'.</p>
  
  <p>Now if I run:</p>
  
  <pre><code>SELECT Parameter
    FROM (SELECT NTH(1, SPLIT(Params,'=')) as Parameter,
          FROM (SELECT 
                AdID,
                NTH(1, SPLIT(DestinationURL,'?')) as baseurl,
                split(NTH(2, SPLIT(DestinationURL,'?')),'&amp;') as Params
                FROM [adwords_accounts_ads.ads_all] 
                HAVING Params CONTAINS 'p='))
  
   GROUP BY 1
  </code></pre>
  
  <p>I get the "group" parameter showing.</p>
  
  <p>question is: shouldn't the</p>
  
  <pre><code>"CONTAINS '='" 
  </code></pre>
  
  <p>condition include the</p>
  
  <pre><code>"CONTAINS 'p='" 
  </code></pre>
  
  <p>In the result? same happens for 't=' instead of '='</p>
  
  <p>Does anyone know how I can fix that? or even how to extract all the parameters from a string that contains a URL?</p>
  
  <p>ps: using LIKE yields the exact same thing</p>
  
  <p>Thanks!</p>