it'll take a bit of work, and you'll need the DelimitedSplit8K function (search SSC and read the article)

things like 02/02 and 02-02 are not dates, so they do not get caught in my example...you'll have to add additional pattern matching on the myfn.Item like i've done with the ISDATE function...something like 'LIKE [0-9][0-9]/[0-9][0-9]

and other similar patterns.

With mySampledata(id,SomeComment)

AS

(SELECT 1,'- aaaaaaa 02/20/2002 jjjjjj sddsdjjjjsdsd sdsds

- asdlajsd fjsdfjkdgn dsjbfks, dfjksflml,fsf,f sdfsdf 9/3/99 sjdfnsdnf sjdfoisofn

- sdkfjos fjsdopfj uyro dlsfl 02-02-02 sflnsldfn sdkflsn

- fdklnsdlnf 02-02 fjsksngjk

- sdkflsdnfl 02/02 hisfdhiif sdjfsdkfk')

SELECT mySampledata.*,

myfn.* ,

Case when IsDate(myfn.Item)=1 THEN CONVERT(datetime,myfn.Item) ELSE NULL END AS PotentialDate

FROM mySampledata

CROSS APPLY dbo.DelimitedSplit8K(SomeComment,' ') Myfn