SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Identifier name
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier users (alias u1)
   Function exists (children 1)
    ExpressionList (children 1)
     Subquery (children 1)
      SelectWithUnionQuery (children 1)
       ExpressionList (children 1)
        SelectQuery (children 3)
         ExpressionList (children 1)
          Asterisk
         TablesInSelectQuery (children 1)
          TablesInSelectQueryElement (children 1)
           TableExpression (children 1)
            TableIdentifier users2 (alias u2)
         Function equals (children 1)
          ExpressionList (children 2)
           Identifier u1.age
           Identifier u2.age
