SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function trimLeft (children 1)
     ExpressionList (children 2)
      Literal \'abc\'
      Function concat (children 1)
       ExpressionList (children 2)
        Literal \'a\'
        Literal \'b\'
