Question

我有这样的疑问,即我们网站上的用户总数为+1:

return db.tblGPlusOneClicks
    .Where(c => 
        c.UserID == UserID
        && c.IsOn
        )
    .Select(c=>c.URLID)
    .Distinct()
    .Count();

数据来源于本表:

“entergraph

单列的URLs,IsOn = 真实的将显示它们拥有的+1 d页数。然而,该表还储存在<代码>IsOn上的贵重物品。

如果是:

Plus one my homepage
Unplus one my homepage

It shouldn t count this as a plus for that user in our query as the last action for this URL for this user was to un-plus 1 it. Similarly, if I:

Plus one my homepage
Unplus one my homepage
Plus one my homepage
Unplus one my homepage
Plus one my homepage

在最初的询问中,它应当把这一点算作,因为对《欧洲统一法》的最后一项行动是加1。

How can I modify my query to count the instances where IsOn is true and that was the last known action for that user for that URL? I m struggling to write a query that does this.

Answer 1

为此:

return db.tblGPlusOneClicks
    .Where(c => c.UserID == UserID)
    .GroupBy(c => c.URLID)
    .Count(g => g.OrderByDescending(c => c.Date).First().IsOn);

Answer 2

你们可以这样做:

return (from c in db.tblGPlusOneClicks
        where c.UserID == UserID
        group c by c.URLID into g
        where g.OrderByDescending(x => x.Date).First().IsOn
        select g.Key).Distinct().Count();

Answer 3

2. 对上下层/下层的平衡可能是什么假设:

return db.tblGPlusOneClicks
    .Where(c => c.UserID == UserID)
    .GroupBy(c=>c.URLID)
    .Select(g => new {
          URLID = g.Key,
          VoteBalance = g.Aggregate(0, (a,i) => a+(i.IsOn?1:-1))
    })
    .Sum(u => u.VoteBalance);

这考虑到了以往的所有投票,而不是仅仅看最新记录。当然,这是你们所希望的。

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