SQL Server 2017

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CREATE TABLE [dbo].[prueba_descarga](
[articulo] [VARCHAR](10) NULL,
[cantidad] [DECIMAL](16, 6) NULL,
[lote] [VARCHAR](10) NULL,
[saldo] [DECIMAL](16, 6) NULL,
[fecha] [DATETIME] NULL,
[descontar] [DECIMAL](16, 6) NULL)

INSERT [dbo].[prueba_descarga] ([articulo], [cantidad], [lote], [saldo], [fecha], [descontar]) VALUES (N'A0001', CAST(65.000000 AS Decimal(16, 6)), N'452', CAST(50.0000000 AS Decimal(22, 7)), CAST(N'2018-06-07T00:00:00.000' AS DateTime), CAST(0.000000 AS Decimal(16, 6)))
INSERT [dbo].[prueba_descarga] ([articulo], [cantidad], [lote], [saldo], [fecha], [descontar]) VALUES (N'A0001', CAST(65.000000 AS Decimal(16, 6)), N'455', CAST(30.0000000 AS Decimal(22, 7)), CAST(N'2018-06-05T00:00:00.000' AS DateTime), CAST(0.000000 AS Decimal(16, 6)))
INSERT [dbo].[prueba_descarga] ([articulo], [cantidad], [lote], [saldo], [fecha], [descontar]) VALUES (N'A0001', CAST(65.000000 AS Decimal(16, 6)), N'456', CAST(10.0000000 AS Decimal(22, 7)), CAST(N'2018-06-11T00:00:00.000' AS DateTime), CAST(0.000000 AS Decimal(16, 6)))
INSERT [dbo].[prueba_descarga] ([articulo], [cantidad], [lote], [saldo], [fecha], [descontar]) VALUES (N'A0002', CAST(20.000000 AS Decimal(16, 6)), N'457', CAST(15.0000000 AS Decimal(22, 7)), CAST(N'2018-06-11T00:00:00.000' AS DateTime), CAST(0.000000 AS Decimal(16, 6)))
INSERT [dbo].[prueba_descarga] ([articulo], [cantidad], [lote], [saldo], [fecha], [descontar]) VALUES (N'A0002', CAST(20.000000 AS Decimal(16, 6)), N'458', CAST(25.0000000 AS Decimal(22, 7)), CAST(N'2018-06-11T00:00:00.000' AS DateTime), CAST(0.000000 AS Decimal(16, 6)))

5 rows affected

articulo	cantidad	lote	saldo	fecha	descontar
A0001	65.000000	455	30.000000	2018-06-05 00:00:00.000	30.000000
A0001	65.000000	452	50.000000	2018-06-07 00:00:00.000	35.000000
A0001	65.000000	456	10.000000	2018-06-11 00:00:00.000	0.000000
A0002	20.000000	457	15.000000	2018-06-11 00:00:00.000	15.000000
A0002	20.000000	458	25.000000	2018-06-11 00:00:00.000	5.000000