Question

我在下面有一个查询，其中列出了当前和上个月男性的销售数量，我想知道这样做是否有效，因为它看起来很重复，如果我得到的话报告一年后查询将非常长。如果我能以任何方式改进此查询，请咨询，我正在考虑性能改进甚至代码减少。感谢。

Declare @CurrentMonth varchar(20)
Declare @PreviousMonth varchar(20)

Set @CurrentMonth =
( 
select count(*) from transact t
join card c
on (t.cardno = c.cardno)
join member m
on (c.Memberid = m.id)

       where mode ='1' 
       and voidby is null
       and gender='M'
       and month(transactdate) = month(getdate())             
)

Set @PreviousMonth = 
(
select count(*) from transact t
join card c
on (t.cardno = c.cardno)
join member m
on (c.Memberid = m.id)

       where mode='1' 
       and voidby is null 
       and gender='M'
       and month(transactdate) = month(dateadd(month, -1, (getdate())))

)

select  @currentMonth, @PreviousMonth

Answer 1

请检查您之前版本的结果。非常重要的是它可以使用transactdate上的索引（如果存在）。

declare @CurMonth int
declare @PrevMonth int

select @PrevMonth = sum(
        case 
        when transactdate < select dateadd(mm, datediff(mm, 0, getdate()), 0)
        then 1 else 0 end
    ),

    @CurMonth = sum(
        case 
        when transactdate > select dateadd(mm, datediff(mm, 0, getdate()), 0)
        then 1 else 0 end
    )
from transact t
join card c on t.cardno = c.cardno
join member m on c.Memberid = m.id
where mode ='1' 
and voidby is null
and gender='M'
and transactdate >= dateadd(mm, datediff(mm, 0, getdate()) - 1, 0)
    and transactdate < dateadd(mm, datediff(mm, 0, getdate()) + 1, 0)

SQL Server +获取当前和上个月的销售查询

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