我的查询过滤没有按我想要的方式工作

Question

我有 3 种过滤方式：

1. 按名称
2. 按列表
3. 并显示全部

我正在使用 ASP.NET 3.5 和 SQL Server 2008。使用 ADO.NET 和存储过程。

我将列表作为表值参数传递（但我正在使用表变量进行测试）并将名称作为 nvarchar 传递。我将“全部显示”为 ISNULL(@var, column) = column。显然，我查询这个的方式没有利用短路或我对 WHERE 子句如何工作的理解缺乏。发生的情况是，如果我创建 @var = 'some string' 并将 null 插入到表变量中，那么它会正确过滤。如果我使@var = null 并将“一些字符串”插入到表变量中，那么我会得到每条记录，我应该得到“一些字符串”。

代码：

declare @resp1 nvarchar(32)
set @resp1 = null
declare @usersTable table
(responsible nvarchar(32))
--insert into @usersTable (responsible) values (null)
insert into @usersTable (responsible) values ('ssimpson')
insert into @usersTable (responsible) values ('kwilcox')
select uT.responsible, jsq.jobnumber, jsq.qid, aq.question, aq.section, aq.seq, answers.* 
from answers
inner join jobno_specific_questions as jsq on answers.jqid = jsq.jqid
inner join apqp_questions as aq on jsq.qid = aq.qid
left join @usersTable as uT on uT.responsible = answers.responsible
where answers.taskAction = 1 and (uT.responsible is not null or ISNULL(@resp1, Answers.responsible) = Answers.responsible)
order by aq.section, jsq.jobnumber, answers.priority, aq.seq

这就是我想出的。虽然很丑....

declare @resp1 nvarchar(32)
set @resp1 = 'rrox'
declare @filterPick int
declare @usersTable table
(responsible nvarchar(32))
insert into @usersTable (responsible) values (null)
--insert into @usersTable (responsible) values ('ssimpson')
--insert into @usersTable (responsible) values ('kwilcox')
if @resp1 is null 
begin
   set @filterPick = 2
end
else
begin
   set @filterPick = 1
end
select uT.responsible, jsq.jobnumber, jsq.qid, aq.question, aq.section, aq.seq, answers.* 
from answers
inner join jobno_specific_questions as jsq on answers.jqid = jsq.jqid
inner join apqp_questions as aq on jsq.qid = aq.qid
left join @usersTable as uT on uT.responsible = answers.responsible
where answers.taskAction = 1 and 
(case
    when uT.responsible is not null then 2
    when ISNULL(@resp1, Answers.responsible) = Answers.responsible then 1          
 end = @filterPick )
order by aq.section, jsq.jobnumber, answers.priority, aq.seq

好的。我想我明白了。我删除了@resp1，因为它不是必需的，我只是使用表值参数@usersTable（但这里我使用表变量进行测试）。我添加了一个标志@filterPick，因此我可以只显示@usersTable 或answers.taskAction = 1 的每条记录中的值。

代码：

declare @filterPick bit 
declare @usersTable table
(responsible nvarchar(32))
insert into @usersTable (responsible) values (null)
--insert into @usersTable (responsible) values ('ssimpson')
--insert into @usersTable (responsible) values ('kwilcox')
if exists (select * from @usersTable where responsible is not null)
   begin
      set @filterPick = 1
   end
else
   begin
      set @filterPick = 0
   end
select *
from answers
inner join jobno_specific_questions as jsq on answers.jqid = jsq.jqid
inner join apqp_questions as aq on jsq.qid = aq.qid
left join @usersTable as uT on answers.responsible = uT.responsible
where answers.taskAction = 1 and (uT.responsible is not null or (isnull(uT.responsible, answers.responsible) = answers.responsible and @filterPick = 0))
order by aq.section, jsq.jobnumber, answers.priority, aq.seq

Answer 1

我对你的问题有点困惑，但我会试一试。

首先，我怀疑您返回的不正确记录的问题与您对空值的比较有关。为了演示我所说的查询您想要的任何表并将其添加到末尾：

WHERE null = null

不会返回任何记录。在你的代码中我会改变：

where answers.taskAction = 1 and (uT.responsible is not null or ISNULL(@resp1, Answers.responsible) = Answers.responsible)

到

where answers.taskAction = 1 and (uT.responsible is not null or @resp1 is null)

然后看看是否返回了想要的结果。

Answer 2

您是否考虑过将 WHERE 子句更改为：

WHERE Answers.taskAction = 1 
AND(ISNULL(@resp1, Answers.responsible) = Answers.responsible 
    OR Answers.responsible IN (SELECT responsible FROM uT))

而不是在表值参数上加入？