SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function equals (children 1)
     ExpressionList (children 2)
      Literal UInt64_2
      Function position (children 1)
       ExpressionList (children 3)
        Literal \'a\'
        Literal \'\'
        Literal UInt64_2