Question

我有一个存储过程，它有两个参数：

@PublishedFrom SMALLDATETIME = NULL,
@PublishedDeadline SMALLDATETIME = NULL

我希望当PublishedDeadline为null时，WHERE条件应为：

WHERE (dbo.Vacancies.StartDate >= @PublishedFrom 
       OR @PublishedFrom IS NULL)

但如果PublishedDeadline不为空，那么WHERE子句应该像

WHERE v.startdate <= @PublishedDeadline 
  and @PublishedFrom <= v.EndDate

如何在SQL中应用条件where子句？

请建议

Answer 1

以下内容对您有用：

WHERE (PublishedDeadline IS NULL 
       AND (
            dbo.Vacancies.StartDate >= @PublishedFrom 
            OR @PublishedFrom IS NULL
       ) OR (
        PublishedDeadline IS NOT NULL 
        AND v.startdate <= @PublishedDeadline 
        AND @PublishedFrom <= v.EndDate
       )

只需将IS NULL / IS NOT NULL条件与其他条件结合起来

Answer 2

由于您使用的是存储过程，因此您可能希望获得更详细，更易读的查询

if (@PublishedDeadline is NULL)
BEGIN
   Select * from dbo.Vacancies
   WHERE (dbo.Vacancies.StartDate >= @PublishedFrom 
   OR @PublishedFrom IS NULL)
END
else
BEGIN
   Select * from dbo.Vacancies
   WHERE v.startdate <= @PublishedDeadline 
    and @PublishedFrom <= v.EndDate
END

sql中的条件where子句用于日期范围

2 个答案: