Question

我的SQL数据库中有以下（简化）结构。

现在我想选择用户尚未加入的所有群组。如果使用Linq / Entity Framework编写查询会有所帮助，但我也可以使用SQL语句。

我尝试使用Include（使用EF）：

.Include(g => g.Group_User)

在查询中而不是使用：

.Where(g => g.Group_User.UserId != userId)

但这不起作用，可能完全不是执行这类查询的正确方法。

感谢您阅读

Answer 1

我想选择用户尚未参与的所有群组。

因此，您希望没有群组用户的所有群组都使用此!Any，因此请使用==和var q = db.Group.Include(g => g.Group_User) .Where(g => !g.Group_User.Any(gu => gu.UserId == userId));：

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SQL / Linq查询选择多对多

1 个答案: