SQL HELP - 基于BIT变量的条件where子句 - SQL Server

Question

我需要帮助编写条件where子句.这是我的情况:

我有一个值来确定在select语句中返回哪些行.如果值为true,我需要返回import_id列不为null的行,如果为false,则我需要import_id列为null的行.

我尝试这样的查询(下面)似乎不起作用,实现这一目标的最佳方法是什么？

DECLARE @imported BIT

SELECT id, import_id, name FROM Foo WHERE
    (@imported = 1 AND import_id IS NOT NULL)
    AND (@imported = 0 AND import_is IS NULL)

谢谢.

Answer 1

更改AND到OR

DECLARE @imported BIT

SELECT id, import_id, name FROM Foo WHERE
    (@imported = 1 AND import_id IS NOT NULL)
    OR (@imported = 0 AND import_is IS NULL)

分解你的原始陈述

你基本上写的

    @imported = 1 
    AND import_id IS NOT NULL
    AND @imported = 0 
    AND import_is IS NULL

相当于

    @imported = 1 AND @imported = 0 
    AND import_id IS NOT NULL AND import_is IS NULL

是什么导致了两对完全否定对方的条款