将 NVARCHAR 列转换为 DATE 数据类型的问题

Question

I have a nvarchar column AddDate and I tried to use alter column to convert it to date , but I get this error

The conversion of a nvarchar data type to a datetime data type resulted in an out-of-range value.

My data looks like this

AddDate
---------------------
10/2/2019 1:06:00 AM
10/28/2019 3:53:00 PM
Mar  6 2020  6:17PM
Feb 20 2020 12:08PM
10/4/2019
10/4/2019

Not sure a possible way to convert them to dd-mm-yyyy or dd/mm/yyyy

Answer 1

try_convert() will work with the sample data.

try_convert() will return a NULL value if the conversion fails.

Example

Declare @YourTable Table ([AddDate] varchar(50))  Insert Into @YourTable Values 
 ('10/2/2019 1:06:00 AM')
,('10/28/2019 3:53:00 PM')
,('Mar 6 2020')
,('Feb 20 2020 12:08PM')
,('10/4/2019')
,('10/4/2019')

Select * 
      ,AsDate   = try_convert(date,AddDate)
      ,AsString = format(try_convert(date,AddDate),'dd-MM-yyyy')
 From @YourTable

Returns

AddDate                 AsDate      AsString
10/2/2019 1:06:00 AM    2019-10-02  02-10-2019
10/28/2019 3:53:00 PM   2019-10-28  28-10-2019
Mar 6 2020              2020-03-06  06-03-2020
Feb 20 2020 12:08PM     2020-02-20  20-02-2020
10/4/2019               2019-10-04  04-10-2019
10/4/2019               2019-10-04  04-10-2019