查詢關於同一對象的兩個ID列

Question

給定一個表是這樣的：

Id_Table | Id_Object_A | Id_Object_B 

並給予ID_Object兩集，我要檢查這個條件：

(ID_Object_A IN (1,2,3,4,5) AND ID_Object_B IN (6,7,8,9,10)) 
OR 
(ID_Object_A IN (6,7,8,9,10) AND ID_Object_B IN (1,2,3,4,5)) 

什麼是最好的方式在性能方面呢？

Answer 1

查詢優化器應該是足夠聰明的最明顯的解決方案有一個可以接受的（接近最佳）性能：

SELECT * 
FROM MyTable 
WHERE (ID_Object_A IN (1,2,3,4,5) AND ID_Object_B IN (6,7,8,9,10)) 
    OR (ID_Object_A IN (6,7,8,9,10) AND ID_Object_B IN (1,2,3,4,5)) 

但SQL Server的真正實力是優化JOIN。生成表的10個號碼的所有50個可能的組合：

CREATE TABLE ReferencesAB (a int NOT NULL, b int NOT NULL) 
CREATE NONCLUSTERED INDEX Covering ON ReferencesAB (a, b) 

INSERT INTO ReferencesAB 
SELECT * 
FROM (VALUES (1), (2), (3), (4), (5)) AS values1 (a) 
CROSS JOIN (VALUES (6), (7), (8), (9), (10)) AS values2 (b) 

INSERT INTO ReferencesAB 
SELECT * 
FROM (VALUES (6), (7), (8), (9), (10)) AS values1 (a) 
CROSS JOIN (VALUES (1), (2), (3), (4), (5)) AS values2 (b) 

然後加入你的表的參考表：

SELECT * 
FROM MyTable t 
INNER JOIN ReferencesAB r ON r.a = Id_Object_A AND r.b = Id_Object_B 

對於這項工作搞好，我認爲這是最好的指標MyTable on (Id_Object_A, Id_Object_B)。

兩種方法的實驗;研究查詢計劃以找出最適合您的表格的方式。