I would suggest that you did this in the end App, as it is a presentation feature rather than a back end, and it it slightly simpler to use.
However, for SQL:
SELECT DATENAME(MONTH, date) + ' ' + DATENAME(YEAR, YEAR(date)) AS Date FROM myTable
In .NET it is easier and cleaner once you have read out the date into a DateTime:
string myDateString = myDate.ToString("MMM yyyy");
There is a list of .NET DateTime.ToString formattoing codes here:
Formatting a DateTime for display - format string description[
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