sql - SQL クエリ - 月の特定の日かどうかを判断する必要があります (例: 月の第 2 火曜日)

Question

ユーザーが将来発生するアクションをスケジュールできるアプリがあります。たとえば、日付を選択して、毎月その日に実行するようにスケジュールできます (例: 毎月 15 日)。ただし、月の曜日と週を選択できるようにする必要があります。たとえば、月の最初の金曜日にアクションを実行する必要があるとします。そのため、平日 (月曜日、火曜日、水曜日など) と週 (1 日、2 日、3 日、4 日、または 5 日) を選択できるようにしています。

現在使用しているクエリは次のとおりです。

Declare @nowString varchar(19)
        Declare @nowDateString varchar(19)
        Declare @now datetime
        Declare @lastMinute datetime
        Declare @nowDate datetime

        Set @nowString = '#currentDateTime#:00'
        Set @nowDateString = LEFT(@nowString, 10)
        set @now = @nowString
        set @nowDate = DATEADD(dd, 0, DATEDIFF(dd, 0, @now))
        set @lastMinute = DATEADD(mi, -1, @now)

        select * 
        from message_prepared
        where schedule = '1' 
        and active = '1'
        and noaa = '0'
        and (
            (
                schedule_type = 'recurring'
                and startdate <= @nowDate
                and isnull(enddate, DATEADD(yy, 1, @nowDate)) >= @nowDate
                and (
                    @nowDateString + ' ' + isnull(recurring_start_time_hour, '00') + ':' + isnull(recurring_start_time_min, '00') + ':00' = @now
                    or @nowDateString + ' ' + isnull(recurring_start_time_hour, '00') + ':' + isnull(recurring_start_time_min, '00') + ':00' = @lastMinute
                )
                -- Test for different type of recurring
                and (
                    ( ltrim(rtrim(recurring)) = 'M' and DATEPART(dd, startdate) = DATEPART(dd, @now) )
                    or ( ltrim(rtrim(recurring)) = 'W' and DATEPART(dw, startdate) = DATEPART(dw, @now) )
                    or ltrim(rtrim(recurring)) = 'D'
                )
            )
            or (
                schedule_type = 'once'
                and startdate = @nowDate
                and (
                    @nowDateString + ' ' + onetime_start_time_hour + ':' + onetime_start_time_min + ':00' = @now
                    or @nowDateString + ' ' + onetime_start_time_hour + ':' + onetime_start_time_min + ':00' = @lastMinute
                )
            )
        )
        and repeat_multiple_times = 0

        UNION ALL

        SELECT *
        FROM MESSAGE_PREPARED
        WHERE schedule = '1' 
        AND active = 1
        AND noaa = 0
        AND recurring = 'D'
        AND repeat_multiple_times = 1
        AND startDate IS NOT NULL
        AND recurring_start_time_hour IS NOT NULL
        AND recurring_start_time_hour < 24
        AND recurring_start_time_min IS NOT NULL
        AND recurring_start_time_min < 60
        AND startdate <= @nowDate
        AND ISNULL(enddate, DATEADD(yy, 1, @nowDate)) >= @nowDate
        AND
        ( 
            CASE WHEN repeat_unit = 'M'
                THEN
                DATEDIFF(n,
                CONVERT(DATETIME, 
                CAST(DATEPART(yyyy, startDate) AS VARCHAR(4)) + '-' + 
                CAST(DATEPART(mm, startDate) AS VARCHAR(2)) + '-' + 
                CAST(DATEPART(dd, startDate) AS VARCHAR(2)) + ' ' + 
                CAST(recurring_start_time_hour AS VARCHAR(2)) + ':' +
                CAST(recurring_start_time_min AS VARCHAR(2)) + ':00', 20),
                GETDATE()) % repeat_interval
                ELSE
                DATEDIFF(n,
                CONVERT(DATETIME, 
                CAST(DATEPART(yyyy, startDate) AS VARCHAR(4)) + '-' + 
                CAST(DATEPART(mm, startDate) AS VARCHAR(2)) + '-' + 
                CAST(DATEPART(dd, startDate) AS VARCHAR(2)) + ' ' + 
                CAST(recurring_start_time_hour AS VARCHAR(2)) + ':' +
                CAST(recurring_start_time_min AS VARCHAR(2)) + ':00', 20),
                GETDATE()) % (repeat_interval * 60)
            END = 0
            OR
            CASE WHEN repeat_unit = 'M'
                THEN
                (DATEDIFF(n,
                CONVERT(DATETIME, 
                CAST(DATEPART(yyyy, startDate) AS VARCHAR(4)) + '-' + 
                CAST(DATEPART(mm, startDate) AS VARCHAR(2)) + '-' + 
                CAST(DATEPART(dd, startDate) AS VARCHAR(2)) + ' ' + 
                CAST(recurring_start_time_hour AS VARCHAR(2)) + ':' +
                CAST(recurring_start_time_min AS VARCHAR(2)) + ':00', 20),
                GETDATE()) - 1) % repeat_interval
                ELSE
                (DATEDIFF(n,
                CONVERT(DATETIME, 
                CAST(DATEPART(yyyy, startDate) AS VARCHAR(4)) + '-' + 
                CAST(DATEPART(mm, startDate) AS VARCHAR(2)) + '-' + 
                CAST(DATEPART(dd, startDate) AS VARCHAR(2)) + ' ' + 
                CAST(recurring_start_time_hour AS VARCHAR(2)) + ':' +
                CAST(recurring_start_time_min AS VARCHAR(2)) + ':00', 20),
                GETDATE()) - 1) % (repeat_interval * 60)
            END = 0
        )

これは、繰り返しが「M」に設定されている場合にのみ発生し、今日が特定の曜日、月の週、時間/分であるかどうかを判断したいと考えています。