Question

我的代码不起作用。我尝试了一些不同的东西，但不知道从哪里开始。我在以下查询中添加了从null开始的值。运行我的代码后，分数值仍为空。

Answers数据库和WeeklyPredictions数据库都有几个属性可用于解决其他问题。这只是使用第一个问题1的代码片段。

    var Q1 = "";
    var weeknumber = "";

    if (IsPost)
    {
        if (Request.Form["weeknumber"] != null)
        {
            weeknumber = Request.Form["weeknumber"];
        }
        if (Request.Form["Question1"] != null)
        {
            string selectedAnswer = Request.Form["Question1"].ToString();
            Q1 = Request.Form["Question1"];
        }


        var db = Database.Open("foo");

        var q1w = ("UPDATE t1 " +
            "SET t1.weeklyScore = t1.weeklyScore + 10, t1.totalScore = t1.totalScore + 10 " +
            "FROM dbo.Scores as t1 " +
            "INNER JOIN dbo.WeeklyPredictions AS t2 " +
            "ON t1.Id = t2.Id " +
            "WHERE t2.Question1 = @0 " +
            "AND t2.WeekNumber = @1");

db.Execute(q1w, Q1, weeknumber);

Answer 1

在SQL NULL + 10中仍然是NULL，请更改您的代码以使用ISNULL(col, 0) + 10

https://technet.microsoft.com/en-us/library/ms191504(v=sql.105).aspx

Answer 2

假设这是SQL Server，我会将其写为：

UPDATE s 
    SET weeklyScore = COALESCE(s.weeklyScore, 0) + 10,
        totalScore = COALESCE(s.totalScore, 0) + 10 
FROM dbo.Scores s INNER JOIN
     dbo.WeeklyPredictions wp
     ON s.Id = wp.Id 
WHERE wp.Question1 = @0 AND wp.WeekNumber = @1;

使用＆＃34;更新＆＃34;增加数据库值和＆＃34;加入＆＃34;一起在SQL查询中

2 个答案: