Question

我正在尝试在tplayoffStatus上创建一个触发器，以便不允许团队插入多个丢失的表中。将值插入表tplayoffStatus时，我一直得到的错误是

子查询返回的值超过1。当子查询遵循=，！=，＆lt;，＆lt; =，＆gt;，＆gt; =或子查询用作表达式时，不允许这样做。

任何人都可以帮我吗？我的SELECT语句在列丢失中返回多个值是错误的吗？

SQL Server 2014表架构：

CREATE TABLE tcollegeFootballTeams
(
    TeamAbbreviation varchar(5) NOT NULL PRIMARY KEY,
    TeamName varchar(50) NOT NULL,
    City varchar(50) NOT NULL,
    State varchar(2) NOT NULL,
    Wins int NOT NULL,
    Losses int NOT NULL
)  

CREATE TABLE tplayoffStatus
(
    TeamName varchar(50) NOT NULL PRIMARY KEY,
    TeamAbbreviation varchar(5) NOT NULL FOREIGN KEY REFERENCES tcollegeFootballTeams(TeamAbbreviation)
); 

CREATE TRIGGER [dbo].[trgNoPlayoffForYou] 
ON [dbo].[tplayoffStatus]
AFTER INSERT
AS
    DECLARE @Losses INT
    DECLARE @ErrorMessage VARCHAR(30)

    SELECT @Losses = (SELECT Losses 
                      FROM dbo.tcollegeFootballTeams 
                      WHERE (Losses > 1))

    IF (@Losses = 'True') 
    BEGIN
        SET @ErrorMessage = 'You may not enter the playoffs with more than 1 loss'
        PRINT @ErrorMessage
        ROLLBACK TRANSACTION
    END

查询1：

INSERT INTO tcollegeFootballTeams (TeamAbbreviation, TeamName, City, State, Wins, Losses)
VALUES ('OSU', 'THE Ohio State University', 'Columbus', 'OH', 10, 2)

[结果] [2]

查询2：

INSERT INTO tcollegeFootballTeams (TeamAbbreviation, TeamName, City, State, Wins, Losses  )
VALUES ('BAMA', 'Alabama', 'Tuscaloosa', 'AL', 12, 0)

[结果] [3]

查询3：

INSERT INTO tcollegeFootballTeams (TeamAbbreviation, TeamName, City, State, Wins, Losses  )
VALUES ('UGA', 'Georgia', 'Athens', 'GA', 11, 1)

[结果] [4]

查询4：

INSERT INTO tcollegeFootballTeams (TeamAbbreviation, TeamName, City, State, Wins, Losses)
VALUES ('CLEM', 'Clemson', 'Clemson', 'SC', 11, 1)

[结果] [5]

查询5：

INSERT INTO tcollegeFootballTeams (TeamAbbreviation, TeamName, City, State, Wins, Losses)
VALUES ('WIS', 'Wisconsin', 'Madison', 'WI', 11, 1)

[结果] [6]

查询6：

INSERT INTO tcollegeFootballTeams (TeamAbbreviation, TeamName, City, State, Wins, Losses)
VALUES ('ND', 'Notre Dame', 'South Bend', 'IN', 10, 2)

[结果] [7]

查询7：

INSERT INTO tcollegeFootballTeams (TeamAbbreviation, TeamName, City, State, Wins, Losses)
VALUES ('OKLA', 'Oklahoma', 'Norman', 'OK', 10, 2)

[结果] [8]

查询8：

INSERT INTO tcollegeFootballTeams (TeamAbbreviation, TeamName, City, State, Wins, Losses)
VALUES ('MIAF', 'Miami of Florida', 'Coral Gables', 'FL', 10, 2)

Answer 1

你的触发错了。您需要在inserted表中查询已插入的记录，并加入tcollegeFootballTeams的{{1}}表

Losses

Answer 2

您可以尝试这样的事情（请记住，损失是数字而不是字符串或布尔值）：

DECLARE @TeamAbbr varchar(5);
Select @TeamAbbr = TeamAbbreviation FROM inserted; /* logic table for record just inserted   */
Select @Losses = Losses FROM dbo.tcollegeFootballTeams WHERE (TeamAbbreviation =  @TeamAbbr);

IF (@Losses > 1) 
BEGIN
    SET  @ErrorMessage = 'You may not enter the playoffs with more than 1 loss'
    Print @ErrorMessage
    Rollback Transaction
END

我在Microsoft SQL Server 2014

2 个答案: