title: Laravel code for GROUP_CONCAT is not working
body: <p>I wanted to create a comma separated results on my Laravel project using MySQL. I know that I have to use the GROUP_CONCAT and I made it work perfectly on mysql using workbench. But I'm having an error when I used it on my Laravel code.
  Please check my actual codes below. When I remove the GROUP_CONCAT line/portion, my code works perfectly.</p>
  
  <p>Error Code when I call my API is: 500(Internal Server Error)</p>
  
  <pre><code> $result = Rmim\WhQcHdr::from('wh_qc_hdrs as hdr')-&gt;select(
          'rr.TrxDate as RR Date',
          'hdr.rr_no as RR No',
          'hdr.inspected_at as Date of Inspection',
          'hdr.qcir_no as QCIR No',
          'hdr.item_code as Item Code',
          'item.ItemDesc as Item Description',
          'hdr.supplier_code as Supplier Code',
          'con.ContactName as Supplier Name',
          'hdr.reject_reason as Reason of Rejection',
          'hdr.cancel_reason as Reason of Cancellation',
          \DB::raw('(CASE WHEN hdr.qc_status="A" THEN "Passed" 
                      WHEN hdr.qc_status="CA" THEN "Conditionally Approved"
                      WHEN hdr.qc_status="R" THEN "Rejected"
                      WHEN hdr.qc_status="C" THEN "Cancelled"
                      ELSE "N/A"
                  END) as Disposition'),
  
          -- line below causes an error when I call my api, it works perfectly if I remove it.
          \DB::raw('GROUP_CONCAT(dtl.parameters) as Failed Parameters')
      )
  
      -&gt;leftJoin('rminv.tbl_rmtrninv as rr', function ($join){
          $join-&gt;on('hdr.rr_no', '=','rr.trxnum')
          -&gt;where('rr.TransID', '=', 2);
      })
      -&gt;leftJoin('rminv.tbl_rmmstitem as item', 'hdr.item_code', '=', 'item.ItemCode')
      -&gt;leftJoin('fginv.tbl_fgmstcontacts as con','hdr.supplier_code','=','con.ContactCode')
      -&gt;leftJoin('crp.wh_qc_dtls as dtl', function ($join){
          $join-&gt;on('hdr.id', '=','dtl.qc_id')
          -&gt;where('dtl.result', '=', 0);
      })
      -&gt;groupBy('rr.TrxDate',
          'hdr.rr_no',
          'hdr.inspected_at',
          'hdr.qcir_no',
          'hdr.item_code',
          'item.ItemDesc',
          'hdr.supplier_code',
          'con.ContactName',
          'hdr.reject_reason',
          'hdr.cancel_reason',
          \DB::raw('(CASE WHEN hdr.qc_status="A" THEN "Passed" 
              WHEN hdr.qc_status="CA" THEN "Conditionally Approved"
              WHEN hdr.qc_status="R" THEN "Rejected"
              WHEN hdr.qc_status="C" THEN "Cancelled"
              ELSE "N/A"
          END)'))
      -&gt;orderBy('hdr.created_at', 'Desc');
  </code></pre>
  
  <p>Thank You In Advance.</p>