SQL Server: query column for data that cannot be cast/converted into datetime
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I have an older table where a `datetime` column was built as a `varchar` and the form inserting data into this table was freeform with no validation/restrictions. I have corrected the form and now am set upon the task of normalizing the data. I need to query this column for all records that cannot be `CAST` as a `datetime`


__example of some of the data__

    9/30/2008
    9/30/13
    august 2010
    5/11
    30SEP12
    31-Mar-2011
    2005

I have already cleaned up the `N/A` data to be `NULL`'s but am unsure of an efficient way of getting everything that would not be considered a valid date. Any hints or tricks or am I going to have to go through record by record to convert this column to a `datetime` data type?