sql - 我的 SqlCode 中的逻辑错误

Question

我需要运行一个报告，给出每个月具有特定创建项的记录计数。对于每个月，我的查询会多次显示该月。难道是我做错了什么：我的脚本：

Select DATEPART(mm,DatePrinted),COUNT(ReceiptNo)As CardPrinted
from mytble where ReceiptNo like'990%'
Group by DatePrinted    

可能的收据：800,75。
预计是这样的：

一月总数

二月总数等。

Answer 1

Use Group by DATEPART(month,DatePrinted).

Select DATEPART(month,DatePrinted) As MyMonth, COUNT(ReceiptNo) As CardPrinted
From mytble 
Where ReceiptNo like '990%'
Group by DATEPART(month,DatePrinted)   

If you need name of the month, then use DATENAME() function:

Select DATENAME(month,DatePrinted) As MyMonth, COUNT(ReceiptNo) As CardPrinted
From mytble 
Where ReceiptNo like '990%'
Group by DATENAME(month,DatePrinted)  

Note: May be you need to group by year to get correct results. Otherwise, you will get the count of similar months regardless of the year. If you are looking for a particular year, add this filter to the WHERE clause Year(DatePrinted) = yourYear

Answer 2

您的 group by 语句是错误的，它必须在DATEPART(mm,DatePrinted)

SELECT DATEPART(mm, DatePrinted) AS [Month], COUNT(ReceiptNo) As CardPrinted
FROM mytble 
WHERE ReceiptNo LIKE '990%'
GROUP BY DATEPART(mm, DatePrinted)

您也可以替换COUNT(ReceiptNo)为COUNT(*)。

另请注意，就像现在一样，不同年份的所有月份都将组合在一起。

如果这不是你想要的行为，你SELECT可以GROUP BY DATEPART(yyyy, DatePrinted), DATEPART(mm, DatePrinted)