SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 2)
    Identifier source.key
    Function max (children 1)
     ExpressionList (children 1)
      Identifier target.key
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (alias source) (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 1)
          ExpressionList (children 2)
           Literal UInt64_1 (alias key)
           Literal \'x\' (alias name)
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      Subquery (alias target) (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 1)
          ExpressionList (children 2)
           Literal UInt64_2 (alias key)
           Literal \'x\' (alias name)
     TableJoin (children 1)
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier source.name
        Identifier target.name
   ExpressionList (children 1)
    Identifier source.key
