如何根据条件重置累计金额?

样本数据:

CREATE TABLE [dbo].[agent_sales]
(
[date] [date] NULL,
[agent] [nvarchar](50) NULL,
[sale] [int] NULL
) ON [PRIMARY]
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-01-03' AS Date), N'Agent A', 10)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-02-05' AS Date), N'Agent A', 5)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-03-10' AS Date), N'Agent A', 20)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-04-10' AS Date), N'Agent A', 2)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-01-05' AS Date), N'Agent B', 5)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-02-06' AS Date), N'Agent B', 28)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-03-10' AS Date), N'Agent B', 5)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-04-10' AS Date), N'Agent B', 10)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-01-02' AS Date), N'Agent C', 35)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-02-04' AS Date), N'Agent C', 25)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-03-08' AS Date), N'Agent C', 15)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-04-10' AS Date), N'Agent C', 10)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-01-01' AS Date), N'Agent D', 5)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-02-02' AS Date), N'Agent D', 35)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-03-10' AS Date), N'Agent D', 31)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-04-10' AS Date), N'Agent D', 10)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-01-01' AS Date), N'Agent E', 32)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-02-01' AS Date), N'Agent E', 0)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-03-10' AS Date), N'Agent E', 20)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-04-10' AS Date), N'Agent E', 12)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-01-01' AS Date), N'Agent F', 32)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-02-02' AS Date), N'Agent F', 9)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-03-10' AS Date), N'Agent F', 11)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-04-10' AS Date), N'Agent F', 12)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-01-01' AS Date), N'Agent G', 32)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-02-02' AS Date), N'Agent G', 0)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-03-10' AS Date), N'Agent G', 20)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-04-10' AS Date), N'Agent G', 8)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-01-01' AS Date), N'Agent H', 32)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-03-10' AS Date), N'Agent H', 20)
GO
INSERT [dbo].[agent_sales] ([date], [agent], [sale]) VALUES (CAST(N'2021-04-10' AS Date), N'Agent H', 8)

SELECT语句输出:

select date, agent, sale
from agent_sales

date                    agent   sales
--------------------------------------
2021-01-03 00:00:00.000 Agent A 10
2021-02-05 00:00:00.000 Agent A 5
2021-03-10 00:00:00.000 Agent A 20
2021-04-10 00:00:00.000 Agent A 2
2021-01-05 00:00:00.000 Agent B 5
2021-02-06 00:00:00.000 Agent B 28
2021-03-10 00:00:00.000 Agent B 5
2021-04-10 00:00:00.000 Agent B 10
2021-01-02 00:00:00.000 Agent C 35
2021-02-04 00:00:00.000 Agent C 25
2021-03-08 00:00:00.000 Agent C 15
2021-04-10 00:00:00.000 Agent C 10
2021-01-01 00:00:00.000 Agent D 5
2021-02-02 00:00:00.000 Agent D 35
2021-03-10 00:00:00.000 Agent D 31
2021-04-10 00:00:00.000 Agent D 10
2021-01-01 00:00:00.000 Agent E 32
2021-02-02 00:00:00.000 Agent E 0
2021-03-10 00:00:00.000 Agent E 20
2021-04-10 00:00:00.000 Agent E 12
2021-01-01 00:00:00.000 Agent F 32
2021-02-02 00:00:00.000 Agent F 9
2021-03-10 00:00:00.000 Agent F 11
2021-04-10 00:00:00.000 Agent F 12
2021-01-01 00:00:00.000 Agent G 32
2021-02-02 00:00:00.000 Agent G 0
2021-03-10 00:00:00.000 Agent G 20
2021-04-10 00:00:00.000 Agent G 8
2021-01-01 00:00:00.000 Agent H 32
2021-03-10 00:00:00.000 Agent H 20
2021-04-10 00:00:00.000 Agent H 8

我想获得累计销售超过30个的代理的计数，但是如果一个代理在过去45天内没有销售30个，计数器(累积和逻辑)应该被重置。

预期输出:

DECLARE @ClosingDay     int =   21
,   @CicleDays      int =   -45
,   @TargetSales    int =   30
;
WITH AgentSaleCicle     AS
(
SELECT  
*
,   CicleBegin  =   DATEADD(DAY, @CicleDays,    CONVERT(date, LTRIM(YEAR([date])*10000+MONTH([date])*100+@ClosingDay)))
,   CicleEnd    =                               CONVERT(date, LTRIM(YEAR([date])*10000+MONTH([date])*100+@ClosingDay))
FROM    [dbo].[agent_sales]
)
,   AgentSaleCicleSum   AS
(
SELECT  
*
--  ,   CicleDays   =   DATEDIFF(DAY, CicleBegin, CicleEnd) 
,   CicleSales  =   (
SELECT  SUM(Sale) 
FROM    [dbo].[agent_sales] IA
WHERE   1=1
AND IA.Agent    =   OA.Agent
AND IA.[Date]   BETWEEN CicleBegin  AND CicleEnd
)
FROM    AgentSaleCicle  OA
)
SELECT 
CicleEnd
,   CicleAgentCount =   SUM(1)
FROM    AgentSaleCicleSum
WHERE   CicleSales  >= @TargetSales
GROUP BY CicleEnd
ORDER BY CicleEnd