Theming on Dates

[Anonymous]

Is it possible to theme layers based on date values? If so, how is this done?

I have a layer with a join to a SQL Server table and I cannot access datetime fields, nor SQL Server functions such as GETDATE() and DATEDIFF(). OK, it seems smalldatetime field types can be accessed, but I'm still not able to use GETDATE() etc. I don' t suppose there are any inbuilt functions in MG that will help? I've only seen one inbuilt function mentioned - the 'concat' function for string manipulation.

Perhaps the SQL Server functions need to be altered in some way in order to be passed on by MapGuide - e.g. the validate option in the Advanced expression builder in Studio complains about the value for units in the DATEDIFF function unless enclosed in single quotes. However, even when I can get the expression to validate, it doesn't have the expected effect in theming the layer (it appears to be ignored). Is there any guidance on building correctly formatted expressions?

Any ideas?

Keith