Fix js error when custom sql query returns no results

pkg/client/client.go

@@ -239,6 +239,11 @@ func (client *Client) query(query string, args ...interface{}) (*Result, error)
 		return nil, err
 	}
 
+	// Make sure to never return null colums
+	if cols == nil {
+		cols = []string{}
+	}
+
 	result := Result{
 		Columns: cols,
 		Rows:    []Row{},

static/js/app.js

@@ -230,7 +230,7 @@ function buildTable(results, sortColumn, sortOrder) {
     return;
   }
 
-  if (!results.rows) {
+  if (results.rows.length == 0) {
     $("<tr><td>No records found</tr></tr>").appendTo("#results");
     $("#results").addClass("empty");
     return;