diff --git a/models/activities/notification.go b/models/activities/notification.go
index dc1b8c6fae..b888adeb60 100644
--- a/models/activities/notification.go
+++ b/models/activities/notification.go
@@ -286,13 +286,14 @@ type UserIDCount struct {
 	Count  int64
 }
 
-// GetUIDsAndNotificationCounts between the two provided times
+// GetUIDsAndNotificationCounts returns the unread counts for every user between the two provided times.
+// It must return all user IDs which appear during the period, including count=0 for users who have read all.
 func GetUIDsAndNotificationCounts(ctx context.Context, since, until timeutil.TimeStamp) ([]UserIDCount, error) {
-	sql := `SELECT user_id, count(*) AS count FROM notification ` +
+	sql := `SELECT user_id, sum(case when status= ? then 1 else 0 end) AS count FROM notification ` +
 		`WHERE user_id IN (SELECT user_id FROM notification WHERE updated_unix >= ? AND ` +
-		`updated_unix < ?) AND status = ? GROUP BY user_id`
+		`updated_unix < ?) GROUP BY user_id`
 	var res []UserIDCount
-	return res, db.GetEngine(ctx).SQL(sql, since, until, NotificationStatusUnread).Find(&res)
+	return res, db.GetEngine(ctx).SQL(sql, NotificationStatusUnread, since, until).Find(&res)
 }
 
 // SetIssueReadBy sets issue to be read by given user.