sql - Converting a table Colum from datetime2 to datetime

Question

I have been assisgned with a starnge assigment where i need to convert 40 tables columns from datetime2 to datetime.

this is the datetime format what i am having in my database.2007-11-12 00:00:00

it contains more than 90,000 records

Please assist

Answer 1

• 您必须检查您的值是否小于 1753 年 1 月 1 日（因为它们与 不兼容datetime）。例如

SELECT * FROM MyTable WHERE MyColumn < '1753-01-01'

• 例如，您必须决定如何处理这些值（这里我将所有 < 1753-01-01 的值更改为 1753-01-01）：

UPDATE MyTable SET MyColumn = '1753-01-01' WHERE MyColumn < '1753-01-01'

• 修改列的类型

ALTER TABLE MyTable ALTER COLUMN MyColumn DATETIME

Answer 2

那只是 rediculos，datetime2 更准确，它具有更大的日期范围并占用相同的字节数（8）。

这是 mssql 的代码：

alter table tablename alter column colname datetime