WHERE选择ALL？ [英] WHERE that selects ALL?

问题描述

我有一个查询，我希望最初调用从数据库捕获所有结果。

I have a query that I wish to initially call to catch all results from a database.

然后，当一个组合框更新时，我希望它捕获列只有 WHERE column = SelectedItemFromComboBox 。

Then, when a combobox is updated, I wish for it to catch the columns only WHERE column = SelectedItemFromComboBox.

我缺少的唯一的东西是一些查询

It's all done; the only thing I am missing is some way to query

SELECT *
FROM Table1
WHERE Column1 = ALL;

这样我可以更新为

SELECT *
FROM Table1
WHERE Column1 = SelectedItemFromComboBox;

我最初可以为设置字符串SelectedItemFromComboBox 以便我返回所有值？

What can I initially set the string for SelectedItemFromComboBoxto so that I return all values?

谢谢。

推荐答案

将 SelectedItemFromComboBox 设置为 null 并将您的查询更改为

Set SelectedItemFromComboBox to null and change your query to

SELECT *
FROM Table1
WHERE Column1 = SelectedItemFromComboBox
or SelectedItemFromComboBox is null

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