不允许从数据类型 datetime 到 int 的隐式转换。使用 CONVERT 函数运行此查询

Question

alter table Garantor alter column [Birth Date] int

Answer 1

尝试这样的事情（您需要创建一个新列，使用转换更新它，删除旧列，然后用旧列重命名新列）

ALTER TABLE dbo.Garantor
ADD newBirthDate int NOT NULL DEFAULT 0 -- NULL and DEFAULT as required
GO

UPDATE dbo.Garantor
SET newBirthDate = CAST([Birth Date] AS int) -- or CONVERT function, it will do the same
GO

ALTER TABLE dbo.Garantor
DROP COLUMN [Birth Date]
GO

SP_RENAME 'dbo.Garantor.newBirthDate', 'dbo.Garantor.[Birth Date]'
GO

Answer 2

转换对我不起作用。 演员也不起作用。 要更改列的数据类型，下面是有效的代码。 将“date”类型更改为“int”类型，只保留年份。

这对我有用：

ALTER TABLE [dbo].[Garantor]
ADD [newBirthDate] int NOT NULL DEFAULT 0
GO

UPDATE [dbo].[Garantor]
SET [newBirthDate] = DATEPART(yyyy,[Birth Date])
GO

ALTER TABLE [dbo].[Garantor]
DROP COLUMN [Birth Date]
GO

SP_RENAME 'dbo.Garantor.newBirthDate', 'dbo.Garantor.[Birth Date]'
GO

另一种解决方案是：

= YEAR([Birth Date])

如果你的表中有索引：

ALTER TABLE [dbo].[Garantor]
ADD [newBirthDate] int NOT NULL DEFAULT 0
GO

UPDATE [dbo].[Garantor]
SET [newBirthDate] = DATEPART(yyyy,[Birth Date])
GO

ALTER TABLE [dbo].[Garantor] DROP CONSTRAINT [UQ__Garantor__1C123681D17FE31B] -- [UQ__Garantor__1C123681D17FE31B] change with your
GO

ALTER TABLE [dbo].[Garantor]
DROP COLUMN [Birth Date]
GO

SP_RENAME 'dbo.Garantor.newBirthDate', 'dbo.Garantor.[Birth Date]'
GO

ALTER TABLE [dbo].[Garantor] ADD UNIQUE NONCLUSTERED 
(
    [Birth Date] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, OPTIMIZE_FOR_SEQUENTIAL_KEY = OFF) ON [PRIMARY]
GO