【ORACLE】SQL查询出每个组中的第一条记录

CREATE TABLE [TestTable] (
[uid] nvarchar(10) NOT NULL ,
[key] nvarchar(10) NOT NULL ,
[value] decimal(10) NOT NULL DEFAULT ((0)))
GO

ALTER TABLE [TestTable] ADD PRIMARY KEY ([uid], [key])
GO

INSERT INTO [dbo].[TestTable] ([uid], [key], [value]) values ('', 'c1', 11)
GO
INSERT INTO [dbo].[TestTable] ([uid], [key], [value]) values ('', 'c2', 12)
GO
INSERT INTO [dbo].[TestTable] ([uid], [key], [value]) values ('', 'c3', 13)
GO
INSERT INTO [dbo].[TestTable] ([uid], [key], [value]) values ('', 'c1', 21)
GO
INSERT INTO [dbo].[TestTable] ([uid], [key], [value]) values ('', 'c2', 22)
GO
INSERT INTO [dbo].[TestTable] ([uid], [key], [value]) values ('', 'c3', 23)
GO

WITH cte AS
(
SELECT *,
ROW_NUMBER() OVER (PARTITION BY uid ORDER BY [key] DESC) AS rn
FROM vtable
)
SELECT *
FROM cte
WHERE rn = 1