SQL - 避免额外GROUP BY（和提高查询性能）

Question

我被困解决这个问题，它应该是不错的听觉新新鲜的想法:)

我有一个表的记录数十亿这样

TAB_IX (int) (PK) 
TAB_ID (int) (PK) 
PR_ID (int) (PK) 
SP_ID (int) (PK)(IX) 
.... 

这样

SELECT TAB_ID, COUNT (SP_ID) as HITS FROM table t 
INNER JOIN table_sp s on t.SP_ID = s.ID 
WHERE TAB_IX = @tab_inx 
AND PR_ID IN (SELECT PR_ID FROM @pr_id) 
AND s.NAME IN (SELECT DISTINCT NAME FROM @sp_names) 
GROUP BY TAB_ID 

table_sp以前我是检索数据与记录10K（ID（INT）（PK），NAME（VARCHAR）（IX））略表

@pr_id和@sp_names是具有一列的表变量

查询非常快（约2-3秒）;现在我不希望像

TAB_IX - TAB_ID - PR_ID - SP_ID 
1  - 700 - 1  - 100 
1  - 700 - 2  - 100 

应被视为一个区分记录不同PR_ID和同TAB_IX，TAB_ID，SP_ID

因此，例如记录。

的唯一方法似乎在做一个额外的GROUP BY

像这样

SELECT TAB_ID, COUNT(SP_ID) as HITS FROM (
SELECT TAB_ID, SP_ID, COUNT (PR_ID) FROM table 
WHERE TAB_IX = @tab_inx 
AND PR_ID in (select PR_ID from @pr_id) 
AND s.NAME IN (SELECT DISTINCT NAME FROM @sp_names) 
GROUP BY TAB_ID, SP_ID) AS DUMMY 
GROUP BY TAB_ID 

问题是性能，因为添加这种额外的GROUP BY操作看起来非常痛苦。

您对改进查询有什么想法吗？

感谢提前:)

Answer 1

我想，在指定要算DISTINCT SP_ID会做的伎俩

SELECT TAB_ID, COUNT (DISTINCT SP_ID) as HITS FROM table t 
INNER JOIN table_sp s on t.SP_ID = s.ID 
WHERE TAB_IX = @tab_inx 
AND PR_ID IN (SELECT PR_ID FROM @pr_id) 
AND s.NAME IN (SELECT DISTINCT NAME FROM @sp_names) 
GROUP BY TAB_ID