是否可以将“ case”与“ count”一起使用？

Question

是否可以使用case并count

 SELECT branches.NAME AS agence, 
       count( 
       CASE loanstatus 
              WHEN '1' 
              AND    Datepart(month,loanaccount.issuedate)= 2 THEN 1 
              ELSE NULL 
       END )AS nombre_de_credits_demande , 
       count( 
       CASE loanstatus 
              WHEN '2' datepart(month,loanaccount.chargeoffdate)= 2 THEN 1 
              ELSE NULL 
       END )AS nombre_de_credits_approuve

请帮我

Answer 1

您可以将其与count() 。 我更喜欢sum() ：

select Branches.Name as Agence,
       sum(case when LoanStatus = '1' and
                     datepart(MONTH, LoanAccount.IssueDate) = 2
                then 1 else 0
           end ) as Nombre_de_Crédits_Demandé ,
       sum(case when LoanStatus = '2' and
                     datepart(MONTH, LoanAccount.IssueDate) = 2
                then 1 else 0
           end ) as Nombre_de_Crédits_Approuvé

您的代码的问题不是count()与sum()而是两种不同case语法的混合。 在case <var> when <val>使用case <var> when <val> ，不能包含任何其他条件。 只需when具有所需的全部条件when使用。

而且，如果您愿意，可以使用count()代替sum() 。

而且，为简洁起见，我更喜欢month()函数：

select Branches.Name as Agence,
       sum(case when LoanStatus = '1' and MONTH(LoanAccount.IssueDate) = 2
                then 1 else 0
           end ) as Nombre_de_Crédits_Demandé ,
       sum(case when LoanStatus = '2' and MONTH(LoanAccount.IssueDate) = 2
                then 1 else 0
           end ) as Nombre_de_Crédits_Approuvé

Answer 2

您可以通过此查询实现目标。

select
branches.name as agence
,(select COUNT(1) from <table_name> where loginstatus=1 and Datepart(month,loanaccount.issuedate)= 2) as nombre_de_credits_demande
,(select COUNT(1) from <table_name> where loginstatus=2 and Datepart(month,loanaccount.issuedate)= 2) as AS nombre_de_credits_approuve
from <Table_name>