问题
I am using MS SQL Server 2008, and in a table I have column idate as date but in the integer format. But in the query I want that in the date format. Is it possible to convert integer date into proper datetime format?
回答1:
You can't convert an integer value straight to a date but you can first it to a datetime then to a date type
select cast(40835 as datetime)
and then convert to a date (SQL 2008)
select cast(cast(40835 as datetime) as date)
cheers
回答2:
You have to first convert it into datetime, then to date.
Try this, it might be helpful:
Select Convert(DATETIME, LEFT(20130101, 8))
then convert to date.
回答3:
You most likely want to examine the documentation for T-SQL's CAST and CONVERT functions, located in the documentation here: http://msdn.microsoft.com/en-US/library/ms187928(v=SQL.90).aspx
You will then use one of those functions in your T-SQL query to convert the [idate] column from the database into the datetime format of your liking in the output.
回答4:
Reading through this helps solve a similar problem. The data is in decimal datatype - [DOB] [decimal](8, 0) NOT NULL - eg - 19700109. I want to get at the month. The solution is to combine SUBSTRING with CONVERT to VARCHAR.
SELECT [NUM]
,SUBSTRING(CONVERT(VARCHAR, DOB),5,2) AS mob
FROM [Dbname].[dbo].[Tablename]
回答5:
If your integer is timestamp in milliseconds use:
SELECT strftime("%Y-%d-%m", col_name, 'unixepoch') AS col_name
It will format milliseconds to yyyy-mm-dd string.
来源：https://stackoverflow.com/questions/7830002/how-to-convert-int-to-date-in-sql-server-2008