Compare Date in Vb.net using Datareader

My req开发者_如何学Pythonuiremnet is i want to compare two data values in my database.These two dates belong to two different columns. What i want to compare is if the date of one column greater by 6 months from the date of other column then it should give error. I want to pass this query to database and check,and later on depending on the result want to insert my other functionality

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If you have two date objects ReturnDate and IssueDate and you want to compare them to check if ReturnDate - IssueDate >= 6 Months:

'For this example the two dates are static and not from database':
Dim ReturnDate = Date.Now
If ReturnDate = Nothing Then ReturnDate = Date.Now 'Not initialized, equal to ReturnDate = Date.MinValue
Dim IssueDate = ReturnDate.AddMonths(-6).AddDays(-1) 'more than 6 Months before
Dim halfYearBefore = ReturnDate.AddMonths(-6)
If IssueDate <= halfYearBefore Then
    'this code will actually go here, show error etc.
End If

If you have problems to retrieve the date-values from dababase with ADO.NET, have a look at following link: http://msdn.microsoft.com/en-us/library/bh8kx08z.aspx