Question

我编写了一个查询来获取Northwind DB的ORDERS表中的所有记录，

select count(*) as COUN,month(OrderDate) as Mon
from orders 
where  Year(OrderDate) = '1996' 
group by month(OrderDate)

这里我要打印所有没有任何记录的月份。任何建议都会有所帮助。

Answer 1

这应该有效：

select count(*) as COUN,month(OrderDate) as Mon
from orders 
where  Year(OrderDate) = '1996' 
AND NOT month(OrderDate) IN(SELECT month(OrderDate) from Orders WHERE Year(OrderDate) = '1996')
group by month(OrderDate)

Answer 2

您可以使用WITH - 系列来生成您感兴趣的月份：

WITH mons AS
  (
    SELECT  1 AS num
    UNION ALL
    SELECT  num + 1
    FROM    mons
    WHERE   num < 12
  )
SELECT COUNT(*) AS COUNT, num
  FROM mons
  LEFT JOIN orders ON MONTH(OrderDate) = num
  WHERE YEAR(OrderDate) = '1996'
  GROUP BY num;

Answer 3

您可以使用having子句来避免两次查询Orders表：

select count(*) as COUN,month(OrderDate) as Mon
from orders 
where  Year(OrderDate) = '1996' 
group by month(OrderDate)
having count(*) = 0

Answer 4

根据this回答，您可以尝试以下方法：

--Example Setup
CREATE TABLE FORDERS (OrderDate datetime)

INSERT INTO FORDERS (OrderDate)
    VALUES (GETDATE());

--Actual Query.
DECLARE @Year varchar(4) = 1996;

DECLARE @StartDate  datetime = @Year + '0101',
        @EndDate    datetime = @Year + '1231';


SELECT  DATENAME(MONTH, DATEADD(MONTH, x.number, @StartDate)) AS MonthName, COUNT(OrderDate)
FROM    master.dbo.spt_values x
    LEFT JOIN FOrders ON x.number = MONTH(OrderDate)
        AND YEAR(OrderDate) = @Year
WHERE   x.type = 'P'        
AND     x.number <= DATEDIFF(MONTH, @StartDate, @EndDate)
GROUP BY x.number, MONTH(OrderDate)
HAVING COUNT(OrderDate) = 0;

SQL Query打印没有记录的月份列表

4 个答案: