Question

以下查询会返回正确的数据，但我想知道是否有更好的方法可以做到这一点。查询应返回过去2个月内存在记录的12个月内每个月的案例数。我们的想法是获得有关月份内订购的帐户数量，以及前两个月中至少一个。另请注意，data_date表中的每个值都将始终是该月的第1个。

SELECT 
sum( 
        case 
            WHEN    a.data_date = '2013-03-01'
                    and exists( 
                            select 1 from sales mth1 
                            where mth1.client_id = a.client_id
                            and 
                                    data_date BETWEEN '2013-01-01' 
                                    and 
                                    '2013-02-01' 

                    ) 
            then case_qty 
            ELSE 0 END
) AS M1 , 
sum( 
        case 
                WHEN a.data_date = '2013-04-01' 
                        and exists( 
                                select 1 from sales mth2 
                                where mth2.client_id = a.client_id 
                                and mth2.data_date BETWEEN '2013-02-01' 
                                        and 
                                        '2013-03-01' 
                        ) 
                then case_qty 
                ELSE 0 END
    ) AS M2 , 
    sum( case WHEN a.data_date = '2013-05-01' and exists( select 1 from sales mth3 where mth3.client_id = a.client_id and mth3.data_date BETWEEN '2013-03-01' and '2013-04-01' )  then case_qty ELSE 0 END) AS M3 , 
    sum( case WHEN a.data_date = '2013-06-01' and exists( select 1 from sales mth4 where mth4.client_id = a.client_id and mth4.data_date BETWEEN '2013-04-01' and '2013-05-01' )  then case_qty ELSE 0 END) AS M4 , 
    sum( case WHEN a.data_date = '2013-07-01' and exists( select 1 from sales mth5 where mth5.client_id = a.client_id and mth5.data_date BETWEEN '2013-05-01' and '2013-06-01' )  then case_qty ELSE 0 END) AS M5 , 
    sum( case WHEN a.data_date = '2013-08-01' and exists( select 1 from sales mth6 where mth6.client_id = a.client_id and mth6.data_date BETWEEN '2013-06-01' and '2013-07-01' )  then case_qty ELSE 0 END) AS M6 , 
    sum( case WHEN a.data_date = '2013-09-01' and exists( select 1 from sales mth7 where mth7.client_id = a.client_id and mth7.data_date BETWEEN '2013-07-01' and '2013-08-01' )  then case_qty ELSE 0 END) AS M7 , 
    sum( case WHEN a.data_date = '2013-10-01' and exists( select 1 from sales mth8 where mth8.client_id = a.client_id and mth8.data_date BETWEEN '2013-08-01' and '2013-09-01' )  then case_qty ELSE 0 END) AS M8 , 
    sum( case WHEN a.data_date = '2013-11-01' and exists( select 1 from sales mth9 where mth9.client_id = a.client_id and mth9.data_date BETWEEN '2013-09-01' and '2013-10-01' )  then case_qty ELSE 0 END) AS M9 , 
    sum( case WHEN a.data_date = '2013-12-01' and exists( select 1 from sales mth10 where mth10.client_id = a.client_id and mth10.data_date BETWEEN '2013-10-01' and '2013-12-01' )  then case_qty ELSE 0 END) AS M10 , 
    sum( case WHEN a.data_date = '2014-01-01' and exists( select 1 from sales mth11 where mth11.client_id = a.client_id and mth11.data_date BETWEEN '2013-11-01' and '2013-12-01' )  then case_qty ELSE 0 END) AS M11  
FROM sales as a 
INNER JOIN Products AS P ON P.product_id = a.product_id  
WHERE a.client_id IN ('123') 
AND a.data_date BETWEEN '2013-03-01' AND '2013-12-01' AND a.case_qty > 0;

Here's a screen shot of the explain

Here's a screen shot of the indexes

Answer 1

更改

data_date BETWEEN'2013-01-01'和'2013-02-01' 至 data_date in（'2013-01-01'，'2013-01-02'，.....，...'2013-02-01'）

但我会将整个查询转换为总和案例，然后使用包装器来提取我需要的帐户。

Answer 2

从您的查询中，您似乎想要一年中产品的年销售额。或者那些影响的东西。因此，根据您的数据，您几乎正在尝试创建一个支点。我有一个类似的问题并像这样解决了它

select
   p.product_id,
   s.client_id,
   sum(case when DATE_FORMAT(a.data_date,'%Y%m') in (201301) then ifnull(case_qty,0) else 0 end) period1,
   sum(case when DATE_FORMAT(a.data_date,'%Y%m') in (201301, 201302) then ifnull(case_qty,0) else 0 end) period2,
   sum(case when DATE_FORMAT(a.data_date,'%Y%m') in (201301, 201302, 201303) then ifnull(case_qty,0) else 0 end) period3,
   sum(case when DATE_FORMAT(a.data_date,'%Y%m') in (201302, 201303, 201304) then ifnull(case_qty,0) else 0 end) period4,
   sum(case when DATE_FORMAT(a.data_date,'%Y%m') in (201303, 201304, 201305) then ifnull(case_qty,0) else 0 end) period5,
   .
   .
   .
   up to period12
from
   sales s
where
   a.data_date between '2013-03-01' and '2013-12-31' and
   s.client_id = some_value
group by
   p.product_id,
   s.client_id

请注意，由于您只对sales表进行一次扫描（取决于where子句和索引中的内容），因此查询的性能大幅提升。为了加快速度，你需要索引例如client_id和data_date。

理想情况下，此查询将针对报表运行，或者其中开始和结束数据已修复且所有用户都可以更改的日期是该日期的年份。我不确定您是否要按product_id分组，因为在您的查询中您不是，但您可以随时将其删除以获得每个客户的总数。

我已根据您在评论中的理解调整了查询。如果你能在case语句中使用关键字'in'，我不是100％肯定。你也可以有更多的案例陈述。

加速具有12个子查询的MySQL查询的方法

2 个答案: