2

我有一张桌子，里面有我们所有的订单。订单链接到一个人。每个人都隶属于一家公司。现在我需要一个在某个日期之前从未订购过的所有公司的列表。查询工作正常，但速度很慢。

这是我的 T-SQL 查询：

SELECT
    DISTINCT p1.company_id
FROM
    order o
    JOIN person p1 ON (o.person_id = p1.id AND p1.company_id IS NOT NULL)
WHERE
    o.orderDate > '2017-01-01'
AND
    o.orderDate < '2017-09-01'
AND NOT EXISTS (SELECT
                    p2.company_id
                FROM
                    order o2
                    JOIN person p2 ON (o2.person_id = p2.id AND p2.company_id = p1.company_id)
                WHERE
                    o2.orderDate < '2017-01-01')

我已经将它从 NOT IN 更改为 NOT EXISTS。因为这是这里大多数人推荐的。没有太大帮助。更好的索引稍微改善了这种情况，但查询仍然很慢。我认为这是因为对于每个订单都必须执行子查询。

这是执行计划： https
://www.brentozar.com/pastetheplan/?id=SyAlAU3db 为简单起见，我在上面的示例中删除了一些 WHERE 子句）

该查询在 Azure SQL（以及用于开发的 SQL Server Express 12）上运行

有人对如何解决这个问题有更好的想法吗？

4

4 回答 4

1

这个是怎么回事。希望我正确理解了任务。

(
  SELECT p1.company_id
  FROM order o
  JOIN person p1 
    ON o.person_id = p1.id 
  WHERE p1.company_id IS NOT NULL
    AND o.orderDate > '2017-01-01'
    AND o.orderDate < '2017-09-01'
)
EXCEPT
(
  SELECT p2.company_id
  FROM order o2
  JOIN person p2 
    ON o2.person_id = p2.id 
  WHERE p2.company_id IS NOT NULL
    AND o2.orderDate < '2017-01-01'
)
于 2017-08-24T13:08:32.013 回答
1

如果您有执行计划要分享，它将有助于性能分析。

我对查询进行了一些更改，如下所示，您可以尝试改进它

SELECT p1.company_id
FROM  order o
INNER JOIN person p1 
    ON (o.person_id = p1.id AND p1.company_id IS NOT NULL)
GROUP BY p1.company_id
HAVING SUM(CASE WHEN  (o.orderDate > '2017-01-01' AND  o.orderDate < '2017-09-01') THEN 1 ELSE 0 END) > 0
      AND
      SUM(CASE WHEN  orderDate < '2017-01-01' THEN 1 ELSE 0 END) = 0
于 2017-08-24T13:02:50.150 回答
0

可能这会帮助你：

WITH cte AS
(
    SELECT o.person_id, MIN(o.orderDate) minOrderDate
        FROM order o 
        GROUP BY o.person_id
)
SELECT DISTINCT p1.company_id
    FROM person p1
    JOIN cte ON cte.person_id = p1.id
    WHERE p1.company_id IS NOT NULL AND cte.minOrderDate > '2017-01-01' AND cte.minOrderDate < '2017-09-01';
于 2017-08-24T13:10:19.130 回答
0

我认为这会做到（哎呀错过了没有订购）

;With FirstOrders
as
(
    Select p1.company_id   
    ,      MIN(o.orderDate) as FirstCompanyOrder
    From Orders o 
    Join Person P1 on o.person_id = p1.id
    Group by P1.Company_id
    Having MIN(o.OrderDate) < '2017-01-01'
)

Select distinct o.company_id
From      Orders      o 
Left join FirstOrders FO on o.Company_id = FO.ComapnyId
where FO.company_id is null
于 2017-08-24T13:02:13.483 回答