Try this one
SELECT u.FirstName, u.LastName, u.DisplayName, u.Email, am.LastLoginDate
FROM {databaseOwner}{objectQualifier}aspnet_Membership AS am INNER JOIN
{databaseOwner}{objectQualifier}aspnet_Users AS au ON am.UserId = au.UserId INNER JOIN
{databaseOwner}{objectQualifier}Users AS u ON au.UserName = u.Username
WHERE
am.UserId NOT IN
(
SELECT UserId
FROM {databaseOwner}{objectQualifier}aspnet_Membership
WHERE LastLoginDate BETWEEN DATEADD(month, - 6, GETDATE()) AND GETDATE()
)
This script is slight modification from Robert's script. It gets all users and then excludes the accounts not login in the past 6 months (using sub query NOT IN)