当日期时间过滤器为 NULL 时，存储过程不返回任何记录？答案

【问题标题】：Stored procedure returns no records when datetime filters are NULL?当日期时间过滤器为 NULL 时，存储过程不返回任何记录？
【发布时间】：2016-03-21 10:12:04
【问题描述】：

考虑这个存储过程：

CREATE PROCEDURE [dbo].[sp_getclients]
    @FromDate datetime, @ToDate datetime
AS
BEGIN
    SET NOCOUNT ON;

    SELECT * 
    FROM CM.Clients
    --If both dates are not NULL then also check PurchaseDate to be between them
    WHERE
        (@FromDate IS NOT NULL AND @ToDate IS NOT NULL 
         AND Clients.PurchaseDate >= @FromDate 
         AND Clients.PurchaseDate <= @ToDate)
        OR
        --If @FromDate is not NULL AND @ToDate IS NULL then also check PurchaseDate to be greater than @FromDate
        (@FromDate IS NOT NULL AND @ToDate IS NULL 
         AND Clients.PurchaseDate >= @FromDate)
        OR
        --If @FromDate is NULL AND @ToDate IS NOT NULL then also check Trans_Date to be less than @ToDate 
        (@FromDate IS NULL AND @ToDate IS NOT NULL 
         AND Clients.PurchaseDate <= @ToDate)
END

当我使用 NULL 参数执行这个存储过程时，不会返回任何记录。

知道我在哪里出错了吗？

【问题讨论】：

(@p IS NULL or col = @p) 对于每个参数。
@jarlh：对于哪个参数？
所有这些，至少是可选的（可为空的）。根据需要使用 rel-op。

标签： sql sql-server stored-procedures sql-server-2012

【解决方案1】：

添加这个：

OR
(@FromDate IS NULL AND @ToDate IS NULL)

【讨论】：