Question

我一直在努力实现条件Where和遇到问题。我想做的只是选择那些去过美容院的客户，这些美容院在过去的一年里都有理发和修指甲。治疗不必在同一天进行。例如如果Susan在过去的12个月内修指甲，请选择Susan在同一时间内理发的所有时间。该表的结构是每次访问都是一行。 e.g。

Customer     Treatment     Treatment_Date
Susan        Manicure      12 Jan 2013
Susan        Make-up       3 Feb 2013
Susan        Haircut       14 Feb 2013
Susan        Blow Dry      3 Mar 2013
Susan        Haircut       21 Apr 2013
Betty        Manicure      4 Jun 2013
Betty        Haircut       7 July 2013
Tara         Haircut       10 Aug 2013

理想情况下，我想选择苏珊和贝蒂。这可以在一个查询中完成，还是必须分解，比如先选择所有理发的客户，然后从中选择那些有修指甲的客户。

提前感谢您的建议。

：）

Answer 1

另一种解决方法

SELECT DISTINCT Customer
  FROM
(
  SELECT Customer,
         MAX(CASE WHEN Treatment = 'Manicure' THEN 1 ELSE 0 END) 
             OVER (PARTITION BY Customer) had_manicure,
         MAX(CASE WHEN Treatment = 'Haircut' THEN 1 ELSE 0 END) 
             OVER (PARTITION BY Customer) had_haircut
    FROM table1 t
   WHERE Treatment_Date >= DATEADD(month, -12, GETDATE())
) q
 WHERE had_manicure + had_haircut = 2

输出：

| CUSTOMER |
|----------|
|    Betty |

这是 SQLFiddle 演示

Answer 2

这是“set-within-sets”子查询的示例。我想使用group by和having来解决这些问题：

select ct.Customer
from CustomerTreatment ct
where ct.Treatment_Date >= getdate() - 365
group by ct.Customer
having sum(case when ct.Treatment = 'Manicure' then 1 else 0 end) > 0 and
       sum(case when ct.Treatment = 'Haircut' then 1 else 0 end) > 0;

having子句中的每个条件都计算每种类型的治疗次数。您的条件指定每个至少出现一次，因此> 0。

Answer 3

Select Customer, Treatment, Treatment_Date From Treatments 
Where Customer In (Select Customer from Treatments Where Treatment = 'Manicure' And Treatment_Date >= Start_Date_For_The_Period_Goes_Here And Treatment_Date <= End_Date_For_The_Period_Goes_Here) 
And 
Customer In (
Select Customer from Treatments Where Treatment = 'Haircut' And Treatment_Date >= Start_Date_For_The_Period_Goes_Here And Treatment_Date <= End_Date_For_The_Period_Goes_Here
)

其他方式：您可以使用between子句。您也可以使用自联接。

在其他新闻中，我不会将此称为条件Where声明。如果Where子句包含Case When Then End短语，我会称之为。

Answer 4

你可以做这样的事情

选择顾客，

 count(case when treatment = 'manicure' then 1 else 0 end) as Manicure,
 count(case when treatment = 'haircut' then 1 else 0 end) as haircut

来自

customerTreatment

其中Treatment_date＆gt; = DATEADD（年，-1，GetDate（））

group by Treatment

have count(Manicure) > 1 and count(haircut) > 1

SQL - 条件Where语句可能吗？

4 个答案:

其他方式：您可以使用between子句。您也可以使用自联接。