如何为Ireport中的多选参数的空值赋值？ [英] How to give condition for null values of multi select parameter in Ireport?

问题描述

我正在使用 iReport 开发报告，我想在其中添加条件对于空值。它使用单选项作为：

I am developing a report using iReport where I want to add a condition for null values. It's working with single select option as:

(city=$P{p_city} or $P{p_city} is null)

这意味着如果我们没有传递city参数的任何值，报告将会起作用，但是这个多选选项不起作用。我们在创建参数时必须在iReport中选择Collection值表达式：

It means here if we do not pass any value for the city parameter, the report will work, but this is not working in case of a multiselect option. We have to choose a "Collection" value expression in iReport when we create a parameter:

($X{IN, country,p_country} or $P{p_country} is null) 

我在 JasperReports Server 来运行此报告。一个是单选，选择城市，另一个是多选，选择国家，报告正在运行而没有传递选择城市参数的值，但对于选择国家参数，我们必须传递该值，因为选择国家/地区是多选项和集合类型参数，并且您不能在查询中为城市参数添加空条件。

I have created two input controls in JasperReports Server to run this report. One is a single select, "Select City" and the other is a multi select, "Select country", and the report is running without passing a value for the "Select city" parameter, but for the "select country" parameter, we must pass the value, because "Select country" is multi select and a Collection type parameter and you can not add null condition in a query as for the city parameter.

如何我们可以修改 JRXML 查询吗？

How we can modify the JRXML query?

推荐答案

$ X功能会自动处理。在您的情况下，您在查询中有这个：

The $X feature handles this automatically. In your case you have this in your query:

$X{IN, country, p_country}

如果您的Collection为null，则转换为 1 = 1 。所以没有理由在查询中添加 $ P {p_country}为空。

That gets converted to 1 = 1 in the case where your Collection is null. So there is no reason to add $P{p_country} is null into the query.

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