用于选择多个记录的存储过程

Question

I need to select records say 2000 from a table with a matching timestamp from c# .net code. Eg:

SELECT * 
FROM ITEMDATA_TABLE 
WHERE ITEMNAME='Item1' and TimeStamp='2010-04-26 17:15:05.667'

The above query has to execute for 2000 items more for the same timestamp.

for this we can use

SELECT * 
FROM ITEMDATA_TABLE 
WHERE ITEMNAME in ('Item1','Item2','Item3','Item4',......) 
  AND TimeStamp='2010-04-26 17:15:05.667'

from SQL Server Management Studio.

I have tried appending all Item names to one string variable and giving it as a parameter to the stored procedure,but it resulted into a wrong concatenation.

How can I do this as a stored procedure executing from the .net code? Can anyone suggest me/correct me in doing this?

Answer 1

If you're on SQL Server 2008 (you didn't mention your version), you can use table-valued parameters .

If you're on SQL Server 2005 or below, check out Erland Sommarskog's excellent articles on how to deal with lists of parameters in stored procedures.

You cannot just pass those in as a string - that does not work.

Answer 2

If doing it from a stored procedure, I would create a temp table of all valid item names, insert into that (ie: just a single table), and do a query against that as the primary, joined to the master where IDs / DateTime qualified. Then delete the temp table.

Answer 3

Following may be the code you are looking for :

SET @SQLString = N'SELECT *
    FROM table1
    WHERE timet = @time and items in (@item)';


DECLARE @SQLString nvarchar(500);
DECLARE @ParmDefinition nvarchar(500);

SET @ParmDefinition = N'@time timestamp,
    @item varchar(max) ';


EXECUTE sp_executesql
    @SQLString
    ,@ParmDefinition
    ,@time = '2010-04-26 17:15:05.667'
    ,@item = '''Item1'',''Item2'',''Item3'',''Item4'''
    ;

Answer 4

不会告诉您以其他方式执行此操作，但是如果您选择了要查找的时间戳的所有项目，然后在c＃代码中迭代此记录集，这会更容易吗？

Answer 5

In SQL 2005 you can pass the list of item as XML parameter to the stored procedure and then write a query against the xml parameter. something like this

SELECT ItemData_Table.* FROM ItemData_Table CROSS APPLY MyxmlParameter.nodes('item') data(i) WHERE ItemData_Table.ItemId = i.value('@itemid', INT)

Here MyxmlParameter is the XML you passed from you .NET code to the stored procedure.