title: bigquery split not returning the right answer
body: <p>I have a dataset of one column (named "path")</p>
  
  <p>Two example records are :</p>
  
  <p>/shop/category/misc/product-one-a3-midnight-black/?sid=spl12345
  /shop/category/misc/product-one-a3-midnight-black/</p>
  
  <pre><code>NTH(1,split(path, '/')) one,
  NTH(2,split(path, '/')) two,
  NTH(3,split(path, '/')) three,
  NTH(4,split(path, '/')) four
  </code></pre>
  
  <p>one always returns "shop"
  two always returns "category"
  three always returns "misc"
  but four returns "?sid=spl12345" for record 1 and "product-one-a3-midnight-black" for record two. I except both records to return "product-one-a3-midnight-black" since they both come after the fourth "/"</p>
  
  <p>When i type it out manually i.e.</p>
  
  <pre><code>SELECT  NTH(1,split(path, '/')) one,
                NTH(2,split(path, '/')) two,
                NTH(3,split(path, '/')) three,
                NTH(4,split(path, '/')) four from
          (SELECT "/shop/category/misc/product-one-a3-midnight-black/?sid=spl12345" AS path),
           (SELECT "/shop/category/misc/product-one-a3-midnight-black/" AS path),
  </code></pre>
  
  <p>It seems to work. But for some reason using my big table in bigquery doesn't work - does anyone know why?</p>