How to convert SQL Server's timestamp column t

问题:

As SQL Server returns timestamp like \'Nov 14 2011 03:12:12:947PM\', is there some easy way to convert string to date format like \'Y-m-d H:i:s\'.

So far I use

date(\'Y-m-d H:i:s\',strtotime(\'Nov 14 2011 03:12:12:947PM\'))

回答1:

SQL Server\'s TIMESTAMP datatype has nothing to do with a date and time!

It\'s just a hexadecimal representation of a consecutive 8 byte integer - it\'s only good for making sure a row hasn\'t change since it\'s been read.

You can read off the hexadecimal integer or if you want a BIGINT. As an example:

SELECT CAST (0x0000000017E30D64 AS BIGINT)

The result is

400756068

In newer versions of SQL Server, it\'s being called RowVersion - since that\'s really what it is. See the MSDN docs on ROWVERSION:

Is a data type that exposes automatically generated, unique binary numbers within a database. rowversion is generally used as a mechanism for version-stamping table rows. The rowversion data type is just an incrementing number and does not preserve a date or a time. To record a date or time, use a datetime2 data type.

So you cannot convert a SQL Server TIMESTAMP to a date/time - it\'s just not a date/time.

But if you\'re saying timestamp but really you mean a DATETIME column - then you can use any of those valid date formats described in the CAST and CONVERT topic in the MSDN help. Those are defined and supported \"out of the box\" by SQL Server. Anything else is not supported, e.g. you have to do a lot of manual casting and concatenating (not recommended).

The format you\'re looking for looks a bit like the ODBC canonical (style = 121):

DECLARE @today DATETIME = SYSDATETIME()

SELECT CONVERT(VARCHAR(50), @today, 121)

gives:

2011-11-14 10:29:00.470

SQL Server 2012 will finally have a FORMAT function to do custom formatting......

回答2:

My coworkers helped me with this:

select CONVERT(VARCHAR(10), <tms_column>, 112), count(*)
from table where <tms_column> > \'2012-09-10\'
group by CONVERT(VARCHAR(10), <tms_column>, 112);

or

select CONVERT(DATE, <tms_column>, 112), count(*)
from table where <tms_column> > \'2012-09-10\'
group by CONVERT(DATE, <tms_column>, 112);

回答3:

Works fine, except this message:

Implicit conversion from data type varchar to timestamp is not allowed. Use the CONVERT function to run this query

So yes, TIMESTAMP (RowVersion) is NOT a DATE :)

To be honest, i fidddled around quite some time myself to find a way to convert it to a date.

Best way is to convert it to INT and compare. Thats what this type is meant to be. If You want a date - just add a Datetime row and live happyly ever after :)

cheers mac

回答4:

The simplest way of doing this is:

SELECT id,name,FROM_UNIXTIME(registration_date) FROM `tbl_registration`;

This gives the date column atleast in a readable format. Further if you want to change te format click here.

回答5:

Using cast you can get date from a timestamp field:

SELECT CAST(timestamp_field AS DATE) FROM tbl_name

回答6:

\"You keep using that word. I do not think it means what you think it means.\" — Inigo Montoya

The timestamp has absolutely no relationship to time as marc_s originally said.

declare @Test table (
     TestId int identity(1,1) primary key clustered
    ,Ts     timestamp
    ,CurrentDt datetime default getdate()
    ,Something varchar(max)
)

insert into @Test (Something)
    select name from sys.tables
waitfor delay \'00:00:10\'

insert into @Test (Something)
    select name from sys.tables

select * from @Test

Notice in the output that Ts (hex) increments by one for each record, but the actual time has a gap of 10 seconds. If it were related to time then there would be a gap in the timestamp to correspond with the difference in the time.

回答7:

Some of them actually does covert to a date-time from SQL Server 2008 onwards.

Try the following SQL query and you will see for yourself:

SELECT CAST (0x00009CEF00A25634 AS datetime)

The above will result in 2009-12-30 09:51:03:000 but I have encountered ones that actually don\'t map to a date-time.

回答8:

Why not try FROM_UNIXTIME(unix_timestamp, format)?

回答9:

Not sure if I\'m missing something here but can\'t you just convert the timestamp like this:

CONVERT(VARCHAR,CAST(ZEIT AS DATETIME), 110)