SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 2)
    Identifier a
    Identifier b
   TablesInSelectQuery (children 3)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier t1 (alias tt1)
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      Subquery (alias tt2) (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 2)
          ExpressionList (children 1)
           Identifier c
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             TableIdentifier t2
     TableJoin (children 1)
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier tt1.a
        Identifier tt2.c
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      Subquery (alias tt3) (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 2)
          ExpressionList (children 1)
           Identifier f
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             TableIdentifier t3
     TableJoin (children 1)
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier tt1.b
        Identifier tt3.f
