图表月份

Question

    Select      substring(convert(nvarchar, A.CreatedAt, 107), 0, 4) as 'Month',
                COUNT(*) as 'Booked',
                sum(cast(A.IsCancelled as int)) as 'Cancelled' 
    From        ReservationTbl A
    group by    substring(convert(nvarchar, A.CreatedAt, 107), 0, 4)

如何获取图表上当年前几个月的数据？ 如果一个月没有数据，该如何声明并过零？

Answer 1

像艾伦·贝特尔森（Allan Bertelsen）所说；将年份和月份的where子句与getdate（）一起使用

Select      substring(convert(nvarchar, A.CreatedAt, 107), 0, 4) as 'Month',
            COUNT(*) as 'Booked',
            sum(cast(A.IsCancelled as int)) as 'Cancelled'

From        ReservationTbl A

where       YEAR(A.CreatedAt) = YEAR(getdate())
            and MONTH(A.CreatedAt) <= MONTH(getdate())

group by    substring(convert(nvarchar, A.CreatedAt, 107), 0, 4)

Answer 2

在where子句中指定上个月和当前月份

Select substring(convert(nvarchar, A.CreatedAt, 107), 0, 4) as 'Month',
      COUNT(*) as 'Booked',
      sum(cast(A.IsCancelled as int)) as 'Cancelled' 
From ReservationTbl A
where YEAR(A.CreatedAt) = YEAR(getdate())
      and MONTH(A.CreatedAt)>= month(DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE()) - 1, 0)) and MONTH(A.CreatedAt) <= MONTH(getdate())
group by substring(convert(nvarchar, A.CreatedAt, 107), 0, 4)