Query a date in a varchar field

Question

I am trying to do a simple query...
Count the number of records in a particular month...
I use variables in the URL and use this query (in MSSQL)
SELECT recorddate FROM sometable
WHERE Year(recorddate) LIKE '#Url.year#'
AND Month(recorddate) LIKE '#Url.month#'
This should work in theory, I believe, but the problem is that the date field is varchar (though all records have a timestamp which has been added as:
<INPUT type="hidden" name="recordate" value="#Now()#">
I'm not that advanced in ColdFusion so I'm hoping someone can help me out... Is there a simple way to do this?
Thanks!

Answer 1

I agree with Dan Bracuk that you should store your date values in a date column.  For SQL server this would be DATETIME, SMALLDATETIME, or DATE depending on your server version and requirements.
As a quick fix you can use a derived table that converts your varchar column values to dates.  Be aware that this should only be used as work around until you can update your table to use a date column.  This query will probably not perform well on large data sets.  You should also use the CFQUERYPARAM tag to avoid SQL injection vulnerabilities.
<cfquery name="report" datasource="mydsn">
    SELECT recorddate
     FROM
         SELECT CONVERT(DATETIME, recorddate) AS recorddate
         FROM sometable
     ) AS Q
     WHERE Year(recorddate) = <cfqueryparam value="#url.year#" cfsqltype="cf_sql_integer" />   
         AND Month(recorddate) = <cfqueryparam value="#url.month#" cfsqltype="cf_sql_integer" />  
</cfquery>