Question

我不确定在where子句中给出这个条件的正确名称是什么。我正在使用Microsoft SQL Server 2008。

基本上，我有一个包含以下列的订单表。

MyOrderTable：

OrderAmount Paid    OrderDate
100         Y       2016-08-10 21:15:52.000
120         N       2016-08-10 20:15:12.000
300         Y       2016-08-09 11:10:22.000
500         Y       2016-06-09 10:10:54.000
125         N       2016-06-09 09:15:13.000 
325         N       2015-11-09 09:15:13.000

目前，我有以下SQL查询：

SELECT DATEPART(Year, OrderDate) TheYear, DATEPART(Month, OrderDate) TheMonth,
       SUM(ISNULL(OrderAmount, 0)) as SumOrderAmount
FROM MyOrderTable
WHERE YEAR(OrderDate) = 2016
GROUP BY DATEPART(Year, OrderDate), DATEPART(Month, OrderDate)
ORDER BY TheYear, TheMonth

从上面的SQL返回的结果如下：

TheYear     TheMonth    SumOrderAmount
2016        6           625
2016        8           520

如何查询SumOrderAmount，其中行是Paid =＆＃39; Y＆＃39;？我想从SQL中返回以下内容：

TheYear     TheMonth    SumOrderAmount  PaidSumOrderAmount
2016        6           625             500
2016        8           520             400

我该怎么做？任何帮助是极大的赞赏。谢谢。

Answer 1

使用case表达式执行条件SUM()：

SELECT DATEPART(Year, OrderDate) TheYear, DATEPART(Month, OrderDate) TheMonth,
       SUM(ISNULL(OrderAmount, 0)) as SumOrderAmount,
       SUM(case when Paid='Y' then OrderAmount end)
FROM MyOrderTable
WHERE YEAR(OrderDate) = 2016
GROUP BY DATEPART(Year, OrderDate), DATEPART(Month, OrderDate)
ORDER BY TheYear, TheMonth

Answer 2

使用条件聚合：

10-08 14:15:59 DEBUG JpaTransactionManager - Creating new transaction with name [es.package.app.repository.jpa.JPAValorMaximo.update]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT; ''
10-08 14:15:59 DEBUG JpaTransactionManager - Opened new EntityManager [org.hibernate.ejb.EntityManagerImpl@405264e8] for JPA transaction
10-08 14:15:59 DEBUG AbstractTransactionImpl - begin
10-08 14:15:59 DEBUG LogicalConnectionImpl - Obtaining JDBC connection
10-08 14:15:59 DEBUG LogicalConnectionImpl - Obtained JDBC connection
10-08 14:15:59 DEBUG JdbcTransaction - initial autocommit status: true
10-08 14:15:59 DEBUG JdbcTransaction - disabling autocommit
10-08 14:15:59 DEBUG JpaTransactionManager - Exposing JPA transaction as JDBC transaction [org.springframework.orm.jpa.vendor.HibernateJpaDialect$HibernateConnectionHandle@1bbb3b9e]
10-08 14:15:59 DEBUG SQL - UPDATE table SET field= LEAST(NUMERADOR/DENOMINADO, ? )
Hibernate: UPDATE table SET field= LEAST(NUMERADOR/DENOMINADO, ? )

您可能不需要SELECT DATEPART(Year, OrderDate) TheYear, DATEPART(Month, OrderDate) TheMonth, SUM(ISNULL(OrderAmount, 0)) as SumOrderAmount, SUM(CASE WHEN Paid = 'Y' THEN OrderAmount ELSE 0 END) as PaidOrderAmount FROM MyOrderTable WHERE YEAR(OrderDate) = 2016 GROUP BY DATEPART(Year, OrderDate), DATEPART(Month, OrderDate) ORDER BY TheYear, TheMonth;中的ISNULL()。在SQL中，SUM()聚合函数中会忽略NULL个值。

Answer 3

在select：

上添加此子句

${MyVersion}

Answer 4

SELECT DATEPART(Year, OrderDate) TheYear, DATEPART(Month, OrderDate) TheMonth,
       SUM(ISNULL(OrderAmount, 0)) as SumOrderAmount,Paid
FROM MyOrderTable
WHERE (YEAR(OrderDate) = 2016) and (Paid = 'Y')
GROUP BY DATEPART(Year, OrderDate), DATEPART(Month, OrderDate)
ORDER BY TheYear, TheMonth

在where子句中添加子条件

4 个答案: