哪里有比赛

Question

我有一个要从中选择的表，该表从登录名中记录“签名”。

该表如下所示：

| Int| VARCHAR  | Guid   | Bit    | Int |  NVARCHAR(MAX)
| ID | UserName | UserId | Signed | Rec | additional info etc...
| -- | -------- | ------ | ------ | --- | ---------------------
| 1  | Bob      | 12     | 0      | 100 | sasdd
| 2  | Steve    | 14     | 1      | 100 | asretg
| 3  | GROUP: 2 | 76     | 0      | 101 | This is a group of logins
| 4  | Bob      | 12     | 1      | 101 | asdfasd

因此，第5列是对其进行签名的目标ID。

为特定用户（Bob）建立未签名项目的列表非常简单：

SELECT Rec FROM tbl_Sigs WHERE Signed = 0 And UserId = '12'

现在，我已将登录组添加到此列表中，如第3项所示-在此示例中，该组中既包含登录名，又能够在代码中从登录名中拉出它有权访问的组，因此语句变为：

SELECT Rec FROM tbl_Sigs WHERE (Signed = 0 And UserId = '12')
    OR UserId IN (76,77,78)

这可行，但是在示例中将选择记录100和101 。

我只想为Bob选择记录100 ，因为由于“ GROUP：2”（我将始终是未签名的），所以我有101个匹配项，但是“ Bob”已经对记录101了签名，因此不需要在他的清单中。

我不知道如何将该条件放入where子句中，但是一旦有了数据集，我就可以在C＃中完成，但如果可能的话，我更喜欢纯SQL方法。

Answer 1

我认为您只需要一个NOT EXISTS子句？

DECLARE @tbl_Sigs TABLE (
    ID INT,
    UserName VARCHAR(50),
    UserId INT, --Not a GUID!
    Signed BIT,
    Rec INT,
    AdditionalInfo VARCHAR(MAX));
INSERT INTO @tbl_Sigs VALUES (1, 'Bob', 12, 0, 100, 'sasdd');
INSERT INTO @tbl_Sigs VALUES (2, 'Steve', 14, 1, 100, 'asretg');
INSERT INTO @tbl_Sigs VALUES (3, 'GROUP: 2', 76, 0, 101, 'This is a group of logins');
INSERT INTO @tbl_Sigs VALUES (4, 'Bob', 12, 1, 101, 'asdfasd');
--So column 5 is the target ID to which it's been signed.
--To build a list of unsigned items for a specific user (Bob) was pretty straight forward:
SELECT Rec FROM @tbl_Sigs WHERE Signed = 0 And UserId = '12';

--Now, I've added login groups to this list, as in item 3 - In this example, the group has both logins in it and I'm able in code to pull from the login, which group it has access to, so the statement becomes:
SELECT Rec FROM @tbl_Sigs r1 WHERE (Signed = 0 And UserId = '12') OR UserId IN (76, 77, 78)
AND NOT EXISTS (SELECT * FROM @tbl_Sigs r2 WHERE r2.Rec = r1.Rec AND r2.UserId = '12' AND r2.Signed = 1);