Question

This is in MS SQL Server.

I have a varchar in the format yyyy-MM-dd-hh.mm.ss.nnnnnn

For example: 2010-09-17-20.52.31.870000

I want to convert this into a datetime… but ISDATE function in MSSQL says that is not a valid date and CONVERT won’t work. Is there a way to use the convert function so that I can tell it what format the date is in?

I also want to check first that it is a valid date since the varchar input may contain nothing or it may contain an invalid date.

For example, invalid data of 2010-xx-r7-99.53esdfd.31.870000… I would skip that data and not even try to convert.

Answer 1

As far as I’m aware, SQL Server 2005 only supports milliseconds up to 3 digits, so you could replace the periods with colons, and grab the left and right portions (ignoring the hyphen between the day and hours) and come up with something like this:

DECLARE @myDate varchar(50)
SET @myDate = '2010-09-17-20.52.31.870000'

PRINT isdate(left(@myDate, 10) + ' ' + 
 replace(substring(@myDate, 12, 12), '.', ':'))  -- Should print '1'

PRINT cast(left(@myDate, 10) + ' ' + 
    replace(substring(@myDate, 12, 12), '.', ':') as datetime)

… which will effectively give you 870 milliseconds