SQL Server 2019

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CREATE TABLE [dbo].[TB_Transactions](
    [Id] [bigint] IDENTITY(1,1) NOT NULL,
    [TransferFromId] [bigint] NULL,
    [TransferToId] [bigint] NULL,
    [Amount] [decimal](21, 8) NOT NULL, 
    [Created] [datetime2](7) NOT NULL,
 CONSTRAINT [PK_FG_Transactions_Id] PRIMARY KEY CLUSTERED 
(
    [Id] ASC
)
)
INSERT INTO TB_Transactions (TransferFromId,TransferToId,Amount,Created) VALUES
     (17,18,5.00000000,'2022-06-22 16:19:19.8960000'),
     (21,17,12.00000000,'2022-06-01 02:04:27.3970000'),
     (14,19,10.00000000,'2022-05-03 15:43:47.0680000'),
     (15,20,23.00000000,'2022-06-07 11:34:32.1580000'),
     (12,21,100.00000000,'2022-05-05 02:54:57.7000000'),
     (15,14,20.00000000,'2022-06-24 12:57:41.0670000'),
     (19,20,43.00000000,'2022-06-10 00:46:35.3150000'),
     (21,17,54.00000000,'2022-05-05 00:18:24.6590000'),
     (15,18,28.00000000,'2022-05-02 22:06:25.3310000'),
     (13,15,62.00000000,'2022-05-06 00:05:51.2740000'),
     (15,NULL,2.00000000,'2022-06-01 01:05:51.2710000'),
     (NULL,17,3.00000000,'2022-06-02 02:05:51.2770000'),
     (19,NULL,20.00000000,'2022-07-02 02:05:45.2000000'),
     (15,19,50.00000000,'2022-07-08 07:05:40.2000000'),
     (14,21,10.00000000,'2022-07-07 08:05:40.2000000'),
     (14,21,10.00000000,'2022-07-08 09:05:40.2010000');

16 rows affected

Id	TransferFromId	TransferToId	Amount	Created	Transferrer	DiffQty	RunningSum	Count
3	14	19	10.00000000	2022-05-03 15:43:47.0680000	14	-10.00000000	-10.00000000	1
6	15	14	20.00000000	2022-06-24 12:57:41.0670000	14	20.00000000	10.00000000	1
15	14	21	10.00000000	2022-07-07 08:05:40.2000000	14	-10.00000000	0.00000000	1
16	14	21	10.00000000	2022-07-08 09:05:40.2010000	14	-10.00000000	-10.00000000	1

Warning: Null value is eliminated by an aggregate or other SET operation.