SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Asterisk
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (alias t1) (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 1)
          ExpressionList (children 1)
           Literal UInt64_2 (alias x)
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      Subquery (alias t2) (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 1)
          ExpressionList (children 3)
           Function CAST (children 1)
            ExpressionList (children 2)
             Function count (children 1)
              ExpressionList (children 1)
               Literal \'x\'
             Literal \'Nullable(Int32)\'
           Function CAST (children 1)
            ExpressionList (children 2)
             Function count (children 1)
              ExpressionList (children 1)
               Literal \'y\'
             Literal \'Nullable(Int32)\'
           Literal UInt64_0 (alias x)
     TableJoin (children 1)
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier t1.x
        Identifier t2.x
