CROSS APPLY性能

Question

是否有可能採取以下SQL提高性能：

SELECT t1.id, 
     t1.name, 
     t2.subname, 
     t2.refvalue 
FROM table1 AS t1 
     CROSS apply (SELECT TOP 1 t2.subid, 
           t2.subname, 
           t3.refvalue 
        FROM table2 AS t2 
          INNER JOIN table3 AS t3 
            ON t2.subid = t3.subid 
        ORDER BY lastupdated DESC) AS t2 

所以它看起來像這樣重寫它：

SELECT t1.id, 
     t1.name, 
     t2.subname, 
     t3.refvalue 
FROM table1 AS t1 
     CROSS apply (SELECT TOP 1 t2.subid, 
           t2.subname 
        FROM table2 AS t2 
        ORDER BY lastupdated DESC) AS t2 
     INNER JOIN table3 AS t3 
       ON t2.subid = t3.subid 

Answer 1

首先，它給出相同的結果？

如果是這樣，查詢計劃說什麼，還有set statistics io on？

Answer 2

Table1，Table2和Table3中有多少行？有多少個相交併最終結果？我試圖找出重寫查詢的目的，並同意gbn ...你是否得到了相同的結果，查詢計劃在兩種情況下看起來是否相同，統計I/O是否更好，以及重寫的查詢運行得更快嗎？