1、实现效果
使用去重或分组，数据库默认按字符排序，特定场景下需自定义排序
原本思路，先去重，再联表保证自定义顺序
改进思路，将 distinct 替换为 group by，再使用 order by 排序中使用 Min关键词
2、原始数据
CREATE TABLE [dbo].[T_Bas_Achievement](
[id] [int] IDENTITY(1,1) NOT NULL,
[name] [nvarchar](50) NULL,
[subject] [nvarchar](50) NULL,
[achievement] [float] NULL,
CONSTRAINT [PK_T_Bas_Achievement] PRIMARY KEY CLUSTERED
(
[id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
SET IDENTITY_INSERT [dbo].[T_Bas_Achievement] ON
GO
INSERT [dbo].[T_Bas_Achievement] ([id], [name], [subject], [achievement]) VALUES (1, N'张三', N'数学', 95.5)
GO
INSERT [dbo].[T_Bas_Achievement] ([id], [name], [subject], [achievement]) VALUES (2, N'李四', N'数学', 80)
GO
INSERT [dbo].[T_Bas_Achievement] ([id], [name], [subject], [achievement]) VALUES (3, N'王五', N'数学', 99)
GO
INSERT [dbo].[T_Bas_Achievement] ([id], [name], [subject], [achievement]) VALUES (4, N'张三', N'语文', 77)
GO
INSERT [dbo].[T_Bas_Achievement] ([id], [name], [subject], [achievement]) VALUES (5, N'李四', N'语文', 88)
GO
INSERT [dbo].[T_Bas_Achievement] ([id], [name], [subject], [achievement]) VALUES (6, N'王五', N'语文', 95)
GO
SET IDENTITY_INSERT [dbo].[T_Bas_Achievement] OFF
GO
3、模拟实现
-- 查看初始数据
select * from T_Bas_Achievement
-- 场景一，分组添加排序
select name,subject from T_Bas_Achievement
group by name,subject
-- 直接分组添加排序，异常
/*
-- 直接添加 id 排序，触发异常
select name,subject from T_Bas_Achievement
group by name,subject
order by id
-- ORDER BY 子句中的列 "T_Bas_Achievement.id" 无效，因为该列没有包含在聚合函数或 GROUP BY 子句中。
*/
-- 使用 order by 排序需添加关键字
select name,subject from T_Bas_Achievement
group by name,subject
order by min(id)
-- 场景二，行转列添加排序
-- 行转列
select b.name,max(b.数学) as 数学,max(b.语文) as 语文 from (select * from T_Bas_Achievement) a pivot (max(achievement) for subject in (数学,语文)) b
group by b.name
-- 行转列添加排序
select b.name,max(b.数学) as 数学,max(b.语文) as 语文 from (select * from T_Bas_Achievement) a pivot (max(achievement) for subject in (数学,语文)) b
group by b.name
order by min(id)
-- 扩展，根据其他数据排序
select ROW_NUMBER() OVER (ORDER BY achievement desc) AS id,name,subject,achievement from T_Bas_Achievement
select b.name,max(b.数学) as 数学,max(b.语文) as 语文 from (select ROW_NUMBER() OVER (ORDER BY achievement desc) AS id,name,subject,achievement from T_Bas_Achievement) a pivot (max(achievement) for subject in (数学,语文)) b
group by b.name
order by min(id)
