SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 2)
    Function leftPad (children 1)
     ExpressionList (children 2)
      Literal \'abc\'
      Literal UInt64_2
    Function leftPad (children 1)
     ExpressionList (children 2)
      Literal \'abc\'
      Function CAST (children 1)
       ExpressionList (children 2)
        Literal \'2\'
        Literal \'Int32\'