Depending how the data in the views is organized could be something like following in SQL
SELECT v1.LoginName,
v1.SoldCount,
v2.PurchaseCount,
v3.ThroughCount
FROM v1
inner join v2 on v1.LoginName = v2.LoginName
inner join v3 on v1.LoginName = v3.LoginName
or if you're doing it in LINQ then perhaps something like
var query =
from v1row in v1
join v2row in v2 on v1row.LoginName equals v2row.LoginName
join v3row in v3 on v1row.LoginName equals v3row.LoginName
select new {
LoginName = v1row.LoginName,
SoldCount = v1row.SoldCount,
PurchaseCount = v2row.PurchaseCount,
ThroughCount = v3row.ThroughCount
}