[英](pass "all" in parameter ?) | how can I make parameter ? in WHERE filter to be a return of ALL in sql request
I am making a wpf C# app following MVVM.我正在按照 MVVM 制作一个 wpf C# 应用程序。 It processes data from accdb (with several connected tables) using DataSet via ServerExplorer.
它通过 ServerExplorer 使用 DataSet 处理来自 accdb(带有多个连接的表)的数据。 I am trying to make a filtered search right now.
我现在正在尝试进行过滤搜索。
SELECT IDBug, [Date], ReportedBy, Replicated, ReproducableSteps, AppArea, Status, FixedVer, FixedBy, Notes, Title
FROM Bugs
WHERE ([Date] >= ?)
AND ([Date] <= ?)
AND (Status = ?)
AND (AppArea = ?)
AND (Replicated = ?)
AND (ReportedBy = ?)
This was working, but only if use all the filter settings.这是有效的,但前提是使用所有过滤器设置。
int idAr = (from DataRow dr in ars.GetData().Rows
where (string)dr["Area"] == AreaSe.ToString()
select (int)dr["IDArea"]).FirstOrDefault();
int idCust = (from DataRow dr in custs.GetData().Rows
where (string)dr["CustomerName"] == CustomS.ToString()
select (int)dr["IDCustomer"]).FirstOrDefault();
BugTable = bugs.GetT(StartDate, StopDate, State, idAr, replicationS, idCust);
I do have some null values in my data, that is why I tried to do smth similar to我的数据中确实有一些空值,这就是为什么我试图做类似于
WHERE Title = ?
WHERE 标题 = ? OR (? IS NULL))
或 (? 是 NULL))
instead of代替
WHERE Title = ?
WHERE 标题 = ?
for each of the parameters.对于每个参数。 But it messes up the data types...
但它弄乱了数据类型......
I don`t think that is smart to write a different sql query for each case, so I need to know how cann I pass "SELECT ALL" to a ?我不认为为每种情况编写不同的 sql 查询是明智的,所以我需要知道如何将“SELECT ALL”传递给 ? parameter.
范围。
You can do use case
in where
clause like this.您可以像这样在
where
子句中使用用case
。 You can pass null
as default value for the parameter.您可以将
null
作为参数的默认值传递。
So it will return the records for @param
if it is not passed else it will return all records.因此,如果未通过,它将返回
@param
的记录,否则它将返回所有记录。
SELECT Col1, Col2….
FROM TableName
WHERE ColName = CASE WHEN @param IS NULL THEN ColName ELSE @param END
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