We have an SSRS report that runs a simple stored procedure, with 2 single-value parameters passed to it. Both the SSRS report and the stored procedure executed in SSMS returns in < 1 second. However, in the course of the last 2 weeks, there's been one user who has had the report not load twice. I've tried clearing the stored procedure's execution plan to no avail, and finally fixed it by just adding a dummy clause (1=1) to the sp to get the plan to change. The report works for every other user, including myself. What would be causing this?
This might be 'parameter sniffing', in which SQL Server generates a query plan for a specific value of the parameter which works ok for that value but works very badly for some other values.
A trick to 'turn off' parameter sniffing is to have some local variables in the stored procedure that are assigned the parameter values before you use them.
CREATE PROCEDURE [GetAroundParameterSniffing]
#SomeID INT
AS
BEGIN
DECLARE #LocalSomeID INT;
SET #LocalSomeID = #SomeID;
SELECT *
FROM MyTable m
WHERE m.SomeID = #LocalSomeID;
END
This forces SQL Server to come up with a plan independent of the parameter value
Data is stored in the SQL database by month. For e.g. TableA_202002, TableA_202001 and so on. The frontend user selects the required Month and Year which is passed on as a parameter into a stored procedure. There maybe other parameters passed in to the SP. In the SP a dynamic query is constructed by including the parameters.
SET #p_SQL = 'SELECT * FROM TABLEA_' + #p_TableName
EXEC (#p_SQL)
I wanted to know if there is a better way of getting the data than building dynamic queries. Thanks
I'm writing a stored procedure which checks for the existence of various tables in various databases, as well as the permissions that the user executing the stored procedure has on those tables. The stored procedure itself resides within a user database (i.e. it's not in the Master db).
To perform my checks, my stored procedure contains lots of SELECT statements. Each of those obviously returns a record set. What I would like is to somehow suppress these record sets so that they are not returned by the stored procedure, and instead return my own, single record set which is just a collection of messages relating to each check the stored procedure performs.
I think the obvious answer is to use a table-valued function instead, but I've not been able to recreate my tests successfully in a Function as they appear in the stored procedure. For starters, I'm having to use temporary tables (not possible in a function) and dynamic SQL (not very compatible with table parameters).
I think I've basically got two choices:
Rewrite my stored procedure as a function and figure out how to do the checks a different way.
Continue using my stored procedure and use an OUTPUT parameter to return my result messages, probably as a delimited string, and in the associated ASP.NET application just ignore all the record sets the stored procedure returns .
Neither of these solutions is very satisfactory. Before I spend any more time pursuing either one, is there a way to discard the record sets produced by the SELECT statements in a stored procedure and explicitly define what record I want it to return?
Hmm, I only can speculate here...
Are you using something like
SELECT ...;
IF ##rowcount > 0
BEGIN
...
END;
?
Then you can rewrite it using something like
IF EXISTS (SELECT ...)
BEGIN
...
END;
or
DECLARE #variable integer;
SELECT #variable = count(*) ...;
IF #variable > 0
BEGIN
...
END;
In general point the results of your queries to a target (variable, table, expression, ...), then they don't get outputted.
And then just execute the query for your desired result in the end.
In my opinion, here is almost no reason to have stored procedures produce record sets. That is what stored functions are for. On occasion, it is needed, because of the use of dynamic SQL or other stored procedures, but not as a general practice. Much, much too often, I see stored procedures being used where stored functions or views are more appropriate.
What should you do? Even SELECT statement in the stored procedure should be one of the following:
Setting (local) variables.
Saving the results in a temporary table or table variable.
The logic for the stored procedure should be working on the local variables. The results should be returned using OUTPUT parameters.
If you need to return rows in a tabular format, you can do that using tables explicitly (such as a global temporary table or real table). Or, you can have one SELECT at the end that does return a single result set. However, if you need this and can phrase the stored procedure as a function, that is better in my opinion.
I'm trying to define a Data Driven Subscription for a report in SSRS 2005.
In Step 3 of the set up you're asked for:
" a command or query that returns a list of recipients and optionally returns fields used to vary delivery settings and report parameter values for each recipient"
This I have written and it returns the data without a hitch. I press next and it rolls onto the next screen in the set up which has all the variables to set for the DDS and in each case it has an option to "Select Value From Database"
I select this radio button and press the drop down. No fields are available to me.
Now the only way I could vary the number of parameters returned by the SP was to have the SP write the SQL to an nvarchar variable and then at the end execute the variable as sql. I have tested this in the Management Studio and it returns the expected fields. I even named them after the fields in SSRS but the thing won't put the field names into the dropdowns.
I've even taken the query body out of the Stored Proc, verified it in SSRS and then tried that. It doesn't work either.
Can anyone shed any light into what I'm doing wrong?
You may need to start your stored proc with something like this:
CREATE PROCEDURE [GetRecipients]
AS
SET NOCOUNT ON
If 1=0
BEGIN
Select CAST(NULL as nvarchar(50)) as RecipientEmail,
CAST(NULL as integer) as Param1,
CAST(NULL as nvarchar(10)) as Param2,
CAST(NULL as DATETIME) as Param3
END
... insert your code here ...
End;
This was needed for a procedure I used as a data source in SSIS that used temp tables. The Select at the top with the format of the final output is never run due to the If contstruct, but it allows SSIS (and possibly SSRS) to see and derive the metadata for the output. I believe that this is due to SSIS and SSRS looking for the first select in your code to try and derive the metadata.
I'm using SQL Server 2005, and I would like to know how to access different result sets from within transact-sql. The following stored procedure returns two result sets, how do I access them from, for example, another stored procedure?
CREATE PROCEDURE getOrder (#orderId as numeric) AS
BEGIN
select order_address, order_number from order_table where order_id = #orderId
select item, number_of_items, cost from order_line where order_id = #orderId
END
I need to be able to iterate through both result sets individually.
EDIT: Just to clarify the question, I want to test the stored procedures. I have a set of stored procedures which are used from a VB.NET client, which return multiple result sets. These are not going to be changed to a table valued function, I can't in fact change the procedures at all. Changing the procedure is not an option.
The result sets returned by the procedures are not the same data types or number of columns.
The short answer is: you can't do it.
From T-SQL there is no way to access multiple results of a nested stored procedure call, without changing the stored procedure as others have suggested.
To be complete, if the procedure were returning a single result, you could insert it into a temp table or table variable with the following syntax:
INSERT INTO #Table (...columns...)
EXEC MySproc ...parameters...
You can use the same syntax for a procedure that returns multiple results, but it will only process the first result, the rest will be discarded.
I was easily able to do this by creating a SQL2005 CLR stored procedure which contained an internal dataset.
You see, a new SqlDataAdapter will .Fill a multiple-result-set sproc into a multiple-table dataset by default. The data in these tables can in turn be inserted into #Temp tables in the calling sproc you wish to write. dataset.ReadXmlSchema will show you the schema of each result set.
Step 1: Begin writing the sproc which will read the data from the multi-result-set sproc
a. Create a separate table for each result set according to the schema.
CREATE PROCEDURE [dbo].[usp_SF_Read] AS
SET NOCOUNT ON;
CREATE TABLE #Table01 (Document_ID VARCHAR(100)
, Document_status_definition_uid INT
, Document_status_Code VARCHAR(100)
, Attachment_count INT
, PRIMARY KEY (Document_ID));
b. At this point you may need to declare a cursor to repetitively call the CLR sproc you will create here:
Step 2: Make the CLR Sproc
Partial Public Class StoredProcedures
<Microsoft.SqlServer.Server.SqlProcedure()> _
Public Shared Sub usp_SF_ReadSFIntoTables()
End Sub
End Class
a. Connect using New SqlConnection("context connection=true").
b. Set up a command object (cmd) to contain the multiple-result-set sproc.
c. Get all the data using the following:
Dim dataset As DataSet = New DataSet
With New SqlDataAdapter(cmd)
.Fill(dataset) ' get all the data.
End With
'you can use dataset.ReadXmlSchema at this point...
d. Iterate over each table and insert every row into the appropriate temp table (which you created in step one above).
Final note:
In my experience, you may wish to enforce some relationships between your tables so you know which batch each record came from.
That's all there was to it!
~ Shaun, Near Seattle
There is a kludge that you can do as well. Add an optional parameter N int to your sproc. Default the value of N to -1. If the value of N is -1, then do every one of your selects. Otherwise, do the Nth select and only the Nth select.
For example,
if (N = -1 or N = 0)
select ...
if (N = -1 or N = 1)
select ...
The callers of your sproc who do not specify N will get a result set with more than one tables. If you need to extract one or more of these tables from another sproc, simply call your sproc specifying a value for N. You'll have to call the sproc one time for each table you wish to extract. Inefficient if you need more than one table from the result set, but it does work in pure TSQL.
Note that there's an extra, undocumented limitation to the INSERT INTO ... EXEC statement: it cannot be nested. That is, the stored proc that the EXEC calls (or any that it calls in turn) cannot itself do an INSERT INTO ... EXEC. It appears that there's a single scratchpad per process that accumulates the result, and if they're nested you'll get an error when the caller opens this up, and then the callee tries to open it again.
Matthieu, you'd need to maintain separate temp tables for each "type" of result. Also, if you're executing the same one multiple times, you might need to add an extra column to that result to indicate which call it resulted from.
Sadly it is impossible to do this. The problem is, of course, that there is no SQL Syntax to allow it. It happens 'beneath the hood' of course, but you can't get at these other results in TSQL, only from the application via ODBC or whatever.
There is a way round it, as with most things. The trick is to use ole automation in TSQL to create an ADODB object which opens each resultset in turn and write the results to the tables you nominate (or do whatever you want with the resultsets). you can also do it in DMO if you enjoy pain.
There are two ways to do this easily. Either stick the results in a temp table and then reference the temp table from your sproc. The other alternative is to put the results into an XML variable that is used as an OUTPUT variable.
There are, however, pros and cons to both of these options. With a temporary table, you'll need to add code to the script that creates the calling procedure to create the temporary table before modifying the procedure. Also, you should clean up the temp table at the end of the procedure.
With the XML, it can be memory intensive and slow.
You could select them into temp tables or write table valued functions to return result sets. Are asking how to iterate through the result sets?