本文提供了一个SQL查询优化的具体案例，展示了如何通过调整查询条件和排序方式来提高查询效率。通过对两个相似但性能不同的SQL语句进行对比，文章强调了合理设置查询参数的重要性。
GO
SELECT TOP 1 * FROM SEC_ITEM WHERE BRAND_ID = 20002 AND (PICKUPTYPE IS NULL OR PickupType<6) AND ((ITEM_STATE = 0 AND (ADMIN_ID<>1 OR (ADMIN_ID=1 AND ITEM_UDATE <'2012-07-04 11:26')) OR (ITEM_STATE = 2 AND ITEM_UDATE <'2012-07-04 11:26'))) ORDER BY Item_CDate
DESC, PICKUPTYPE ASC, ITEM_UDATE DESC
GO
--最优
SELECT TOP 1 * FROM SEC_ITEM WHERE BRAND_ID = 20002 AND (PICKUPTYPE IS NULL OR PickupType<6) AND ((ITEM_STATE = 0 AND (ADMIN_ID<>1 OR (ADMIN_ID=1 AND ITEM_UDATE <'2012-07-04 13:40')) OR (ITEM_STATE = 2 AND ITEM_UDATE <'2012-07-04 13:40'))) ORDER BY Item_CDate
DESC
GO
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