Generate Guid for a specific DateTime (i.e. not for Now)

[pethopal]

Hi, I used RT.Comb succesfully many years. (In SQL Server these Guids can even be used as Primary Keys)

For efficient querying purposes can I generate a Guid for a Specific DateTime.
(Note I will use it for only in SQL Where '>', '<' clause.

Thanks...

[richardtallent]

That's great to hear! I use them for PKs in a number of projects as well in MSSQL / AzureDB projects.

You can query for COMBs falling within a date range. If your SQL is being dynamically generated from .NET code, you can just create the boundary COMBs for your query parameters like this (untested):

var fromComb = provider.Create(Guid.Empty, startDateTime);
var toComb = provider.Create(new Guid("FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF", endDateTime);

If you're looking to convert from a date range to a COMB query directly in T-SQL (for example, feeding datetime values to a stored procedure and having it search on the COMB values), you can use the T-SQL examples shown in the README for your chosen provider to combine the "empty" and "full" GUID values with your start and end datetime values, respectively.

Either way, you'll be able to take full advantage of indexing. It's not as efficient as a "real" datetime column and index, of course, but it's fine for a wide range of use cases.