Question

我有这个在MS SQL Server上运行的查询：

SELECT o.phone AS Number, o.code AS Code, o.name AS Name,
o.expireDate AS ExpireDate, o.disabled AS cardStatus, a.disabled AS AccountStatus, 
MAX(j.cDate) AS LastUse 
FROM [DATAB].[dbo].[Card] AS o
LEFT OUTER JOIN [DATAB].[dbo].[journal] AS j 
ON j.phone = o.phone,
[DATAB].[dbo].[CardType] AS ct, [DATAB].[dbo].[Account] AS a, 
[DATAB].[dbo].[CardProduct] AS cp
WHERE o.accountProductId = ct.id
AND ct.accountId = a .id
AND a.number = 'XXXXXXXXXX' 
AND ct.partnerProductId = cp.id
AND cp.code = 'XXXX'
GROUP BY o.phone, o.code, o.disabled, o.name, o.expireDate, a.disabled
ORDER BY o.name ASC;

我想优化它以便更快地运行，但不要如何开始。

仅供参考，我已经检查了估计的执行计划，DATAB的索引分析。[dbo]。[journal]说它占查询的70％，但没有索引问题消息。

Answer 1

以下是使用Outer Apply

的一种方法

SELECT o.phone      AS Number,
       o.code       AS Code,
       o.name       AS Name,
       o.expireDate AS ExpireDate,
       o.disabled   AS cardStatus,
       a.disabled   AS AccountStatus,
       LastUse
FROM   [DATAB].[dbo].[Card] AS o
       INNER JOIN [DATAB].[dbo].[CardType] AS ct
               ON o.accountProductId = ct.id
       INNER JOIN [DATAB].[dbo].[Account] AS a
               ON ct.accountId = a .id
       INNER JOIN [DATAB].[dbo].[CardProduct] AS cp
               ON ct.partnerProductId = cp.id
       OUTER apply (SELECT Max(cDate)
                    FROM   [DATAB].[dbo].[journal] AS j
                    WHERE  j.phone = o.phone) ou (LastUse)
WHERE  a.number = 'XXXXXXXXXX'
       AND cp.code = 'XXXX'
ORDER  BY o.name ASC;

在phone,cDate表的journal列上创建非聚集索引应该有助于查询

如何优化SQL查询

1 个答案: