结合不同count（*）sql查询的结果

Question

我写了一个查询，用于从microsoft sql server数据库中检索数据。目标是计算带有图片的账单数量和细分所代表的区域中的账单总数我写的查询工作正常，但需要很多时间来获取结果。在普通的电脑上大约需要4-5分钟但是在电脑上有更高的内存需要不到一分钟。因为我不是sql的专家，如果可能的话，我需要帮助优化我的查询。这是查询请告诉我是否可以进一步优化。

SELECT [sub division], 
       [total bills], 
       [pic bills], 
       ( ( t1.[pic bills] * 100 ) / t2.[total bills] ) AS '%' 
FROM   (SELECT gbsdiv   AS 'Sub Division', 
               Count(*) AS 'Pic Bills' 
        FROM   tblgbmain 
        WHERE  ( gbpicture1 IS NOT NULL 
                  OR gbpicture2 IS NOT NULL ) 
               AND gbbatch = 15 
        GROUP  BY gbsdiv) t1 
       INNER JOIN (SELECT gbsdiv   AS 'Sub Division1', 
                          Count(*) AS 'Total Bills' 
                   FROM   tblgbmain 
                   WHERE  gbsdiv IN (SELECT gbsdiv 
                                     FROM   tblgbmain 
                                     WHERE  ( gbpicture1 IS NOT NULL 
                                               OR gbpicture2 IS NOT NULL ) 
                                            AND gbbatch = 15 
                                     GROUP  BY gbsdiv) 
                          AND gbbatch = 15 
                   GROUP  BY gbsdiv) t2 
               ON t1.[sub division] = t2.[sub division1]