There is a SQL script with some declared variables. I want to run this script for various sets of values of these variables and see the outputs. How do I do this?
Just a note: this answer is copied from here but is a great resource for what you are asking.
More examples for set-based vs. procedural can be found here, here and here.
And here is an actual example in SQL code:
DECLARE #someFlag INT
SET #someFlag = 0
WHILE (#someFlag <=5)
BEGIN
PRINT #someFlag
SET #someFlag = #someFlag + 1
END
GO
If you have the appropriate permissions to do it, you could set up the script as a stored procedure and then run the procedure multiple times. Reference on how to do it: http://msdn.microsoft.com/en-us/library/ms187926(v=sql.100).aspx
You don't have to make a permanent proc either, if you don't need it or want it in whatever database you're running it in, you can set it up as a temp proc instead.
So instead of CREATE PROCEDURE dbo.usp_SomeProcedure AS ....
you would do CREATE PROCEDURE #usp_SomeProcedure
Your other option is to put your script into an nvarchar(max) variable and use that along with your other variables to run sp_executesql (http://msdn.microsoft.com/en-us/library/ms188001.aspx).
I would either use a Cursor or a While loop (preference would be the While). It would be something like this
DECLARE #i INT
SET #i = 1
WHILE (#i <=10)
BEGIN
-- do whatever you need to do
SET #i = #i + 1
END
Related
I have the following SQL code:
DECLARE #i INT = 1;
DECLARE #sql_code varchar(max) = '';
DECLARE #repeats INT = 4;
WHILE #i <= #repeats
BEGIN
SET #sql_code = #sql_code+'SELECT ''foo'+cast(#i as varchar)+''' as bar UNION ALL '
SET #i = #i + 1
END;
SET #sql_code = LEFT(#sql_code,LEN(#sql_code) - 10)
exec (#sql_code)
,which when run in SSMS produces this:
bar
----
foo1
foo2
foo3
foo4
How can I reproduce the same result as view (dynamically)?
I know you can't use declarations in view, but could it be done through stored procedure or function?
You can't use dynamic sql inside a view. But yes you can create table valued User-Defined functions as mentioned in this post.
Link to the post: https://social.msdn.microsoft.com/Forums/sqlserver/en-US/3cdeda6c-af19-46e9-b89f-e575fecd475b/dynamic-query-in-view?forum=transactsql
Answer by Gavin Campbell should give you the idea of what can be done.
Note : For more information on Table valued User-Defined Functions: Visit this documentation:
https://learn.microsoft.com/en-us/previous-versions/sql/sql-server-2008-r2/ms191165(v=sql.105)?redirectedfrom=MSDN
Actually, despite what Utsav's good answer says, you can do anything if you put your mind to it. đ
While this is generally not recommended (this answer is for informational purposes), there are certain use cases where it makes sense to use OPENQUERY() inside a View. OPENQUERY() allows you to execute raw SQL against a remote or local SQL Server. Either in the raw SQL itself, or probably more organized in a stored procedure, there's essentially no limitations on the queries you can run, including dynamic SQL.
Example:
CREATE PROCEDURE dbo.RunSomeDynamicSQL
AS
DECLARE #DynamicSQL NVARCHAR(MAX) =
'
SELECT 1 AS Foobar;
';
EXEC sp_executesql #DynamicSQL;
GO
CREATE VIEW dbo.SomeViewThatExecutesDynamicSQL
AS
SELECT Foobar
FROM OPENQUERY
(
LocalServerName,
'
EXEC YourDatabaseName.dbo.RunSomeDynamicSQL
WITH RESULT SETS
((
Foobar INT
));
'
);
GO
SELECT Foobar
FROM dbo.SomeViewThatExecutesDynamicSQL;
You'll notice I'm using the WITH RESULT SETS keyword when executing my procedure inside of OPENQUERY(). This is because OPENQUERY() needs to know the shape of the result set from the executing query. This is one way to describe that when executing a procedure.
One use case for using OPENQUERY() in a View is so you can maximize your ability to performance tune your query (e.g. inside a stored procedure) without losing consumability of the database object.
One important fact about using OPENQUERY() is that the SQL Server Engine always estimates the cardinality of the results to be 10,000 rows. This means if your result set is much larger than 10,000 rows, for example 10 million rows, then you may not get the most optimal execution plan to serve your query.
Also, despite my informational answer, you can of course use a stored procedure alone if that's sufficient for your use case.
could it be done through stored procedure
Sure, just wrap a stored procedure around your code:
CREATE PROCEDURE dbo.SomeStoredProcedure
AS
DECLARE #i INT = 1;
DECLARE #sql_code NVARCHAR(MAX) = '';
DECLARE #repeats INT = 4;
WHILE #i <= #repeats
BEGIN
SET #sql_code = #sql_code+'SELECT ''foo'+cast(#i as varchar)+''' as bar UNION ALL '
SET #i = #i + 1
END;
SET #sql_code = LEFT(#sql_code,LEN(#sql_code) - 10)
EXEC sp_executesql #sql_code
Note I changed the last line of your code to use sp_executesql because it minimizes your risk for SQL injection issues. You should always use that procedure for dynamic SQL execution instead of directly executing your SQL string.
If youâre writing dynamic SQL, always add a Debug mode. It doesnât have to be anything fancy at first, just something like:
IF #Debug = 1 BEGIN PRINT #MySQLInjectionGift END;
How can we use the above script in our Stored procedure
It can be used as a parameter to inject code.
DROP PROC IF EXISTS dbo.usp_myproc
GO
CREATE PROC dbo.usp_myproc (#Debug bit = 0)
AS
BEGIN
DECLARE #MySQLInjectionGift varchar(max) ='a=''HI THERE'','
DECLARE #SQL varchar(max) =
'
SELECT TOP 3'+IIF(#Debug=1,#MySQLInjectionGift,'')+'* FROM SYS.TABLES
'
EXEC (#SQL)
END
GO
EXEC usp_myproc
GO
EXEC usp_myproc #Debug = 1
You can do anything with it like create WHERE clauses on the fly, create columns that do calculations that are not part of the actual query but helpful in debugging. Typical injection include arbitrary SQL select statements that show progress from one SQL to another as when the stored procedure is large, the decision execution path may not be clear especially when there are lots of conditional statement. The debug mode can also run start-up code that can prepare the data or execute a unit test at the end of the query.
Is it possible to use T-SQL programming constructs outside the confines of stored procedures and functions? Specifically, can they be used in ad-hoc sql scripts? If so, is the full range of capabilities available (aside from passing in parameters and returning values that I guess would only be supported in stored procedures and functions)?
I'm from an Oracle PL/SQL background. PL/SQL can be used in stored procedures and functions, but also within anonymous PL/SQL code blocks that can be used in ad-hoc sql scripts and do not get stored in the DB. I'd like to know if T-SQL has similar capabilities.
Yes they can take this example solution to the fizzbuzz problem:
declare #counter int
declare #output varchar(15)
set #counter = 1
while #counter < 101
begin
set #output = ''
if #counter % 3 = 0
set #output = 'Fizz'
if #counter % 5 = 0
set #output = #output + 'Buzz'
if #output =''
set #output = #counter
print #output
set #counter = #counter + 1
end
Of course don't fall into the trap of using procedural code to work with data, SQL works best treating data as a set.
In SQL Server 2005, is there a concept of a one-time-use, or local function declared inside of a SQL script or Stored Procedure? I'd like to abstract away some complexity in a script I'm writing, but it would require being able to declare a function.
Just curious.
You can create temp stored procedures like:
create procedure #mytemp as
begin
select getdate() into #mytemptable;
end
in an SQL script, but not functions. You could have the proc store it's result in a temp table though, then use that information later in the script ..
You can call CREATE Function near the beginning of your script and DROP Function near the end.
Common Table Expressions let you define what are essentially views that last only within the scope of your select, insert, update and delete statements. Depending on what you need to do they can be terribly useful.
I know I might get criticized for suggesting dynamic SQL, but sometimes it's a good solution. Just make sure you understand the security implications before you consider this.
DECLARE #add_a_b_func nvarchar(4000) = N'SELECT #c = #a + #b;';
DECLARE #add_a_b_parm nvarchar(500) = N'#a int, #b int, #c int OUTPUT';
DECLARE #result int;
EXEC sp_executesql #add_a_b_func, #add_a_b_parm, 2, 3, #c = #result OUTPUT;
PRINT CONVERT(varchar, #result); -- prints '5'
The below is what I have used i the past to accomplish the need for a Scalar UDF in MS SQL:
IF OBJECT_ID('tempdb..##fn_Divide') IS NOT NULL DROP PROCEDURE ##fn_Divide
GO
CREATE PROCEDURE ##fn_Divide (#Numerator Real, #Denominator Real) AS
BEGIN
SELECT Division =
CASE WHEN #Denominator != 0 AND #Denominator is NOT NULL AND #Numerator != 0 AND #Numerator is NOT NULL THEN
#Numerator / #Denominator
ELSE
0
END
RETURN
END
GO
Exec ##fn_Divide 6,4
This approach which uses a global variable for the PROCEDURE allows you to make use of the function not only in your scripts, but also in your Dynamic SQL needs.
In scripts you have more options and a better shot at rational decomposition. Look into SQLCMD mode (SSMS -> Query Menu -> SQLCMD mode), specifically the :setvar and :r commands.
Within a stored procedure your options are very limited. You can't create define a function directly with the body of a procedure. The best you can do is something like this, with dynamic SQL:
create proc DoStuff
as begin
declare #sql nvarchar(max)
/*
define function here, within a string
note the underscore prefix, a good convention for user-defined temporary objects
*/
set #sql = '
create function dbo._object_name_twopart (#object_id int)
returns nvarchar(517) as
begin
return
quotename(object_schema_name(#object_id))+N''.''+
quotename(object_name(#object_id))
end
'
/*
create the function by executing the string, with a conditional object drop upfront
*/
if object_id('dbo._object_name_twopart') is not null drop function _object_name_twopart
exec (#sql)
/*
use the function in a query
*/
select object_id, dbo._object_name_twopart(object_id)
from sys.objects
where type = 'U'
/*
clean up
*/
drop function _object_name_twopart
end
go
This approximates a global temporary function, if such a thing existed. It's still visible to other users. You could append the ##SPID of your connection to uniqueify the name, but that would then require the rest of the procedure to use dynamic SQL too.
Just another idea for anyone that's looking this up now. You could always create a permanent function in tempdb. That function would not be prefixed with ## or # to indicate it's a temporary object. It would persist "permanently" until it's dropped or the server is restarted and tempdb is rebuilt without it. The key is that it would eventually disappear once the server is restarted if your own garbage collection fails.
The scope of the function would be within TempDB but it could reference another database on the server with 3 part names. (dbname.schema.objectname) or better yet you can pass in all the parameters that the function needs to do its work so it doesn't need to look at other objects in other databases.
I'm not talking about doing a "SET NOCOUNT OFF". But I have a stored procedure which I use to insert some data into some tables. This procedure creates a xml response string, well let me give you an example:
CREATE PROCEDURE [dbo].[insertSomeData] (#myParam int) AS
DECLARE #reply varchar(2048)
... Do a bunch of inserts/updates...
SET #reply = '<xml><big /><outputs /></xml>'
SELECT #reply
GO
So I put together a script which uses this SP a bunch of times, and the xml "output" is getting to be too much (it's crashed my box once already).
Is there a way to suppress or redirect the output generated from this stored procedure? I don't think that modifying this stored procedure is an option.
thanks.
I guess i should clarify. This SP above is being called by a T-SQL Update script that i wrote, to be run through enterprise studio manager, etc.
And it's not the most elegant SQL i've ever written either (some psuedo-sql):
WHILE unprocessedRecordsLeft
BEGIN
SELECT top 1 record from updateTable where Processed = 0
EXEC insertSomeData #param = record_From_UpdateTable
END
So lets say the UpdateTable has some 50k records in it. That SP gets called 50k times, writing 50k xml strings to the output window. It didn't bring the sql server to a stop, just my client app (sql server management studio).
The answer you're looking for is found in a similar SO question by Josh Burke:
-- Assume this table matches the output of your procedure
DECLARE #tmpNewValue TABLE ([Id] int, [Name] varchar(50))
INSERT INTO #tmpNewValue
EXEC [ProcedureB]
-- SELECT [Id], [Name] FROM #tmpNewValue
I think I found a solution.
So what i can do now in my SQL script is something like this (sql-psuedo code):
create table #tmp(xmlReply varchar(2048))
while not_done
begin
select top 1 record from updateTable where processed = 0
insert into #tmp exec insertSomeData #param=record
end
drop table #tmp
Now if there was a even more efficient way to do this. Does SQL Server have something similar to /dev/null? A null table or something?
Answering the question, "How do I suppress stored procedure output?" really depends on what you are trying to accomplish. So I want to contribute what I encountered:
I needed to supress the stored procedure (USP) output because I just wanted the row count (##ROWCOUNT) from the output. What I did, and this may not work for everyone, is since my query was already going to be dynamic sql I added a parameter called #silentExecution to the USP in question. This is a bit parameter which I defaulted to zero (0).
Next if #silentExecution was set to one (1) I would insert the table contents into a temporary table, which is what would supress the output and then execute ##ROWCOUNT with no problem.
USP Example:
CREATE PROCEDURE usp_SilentExecutionProc
#silentExecution bit = 0
AS
BEGIN
SET NOCOUNT ON;
DECLARE #strSQL VARCHAR(MAX);
SET #strSQL = '';
SET #strSQL = 'SELECT TOP 10 * ';
IF #silentExecution = 1
SET #strSQL = #strSQL + 'INTO #tmpDevNull ';
SET #strSQL = #strSQL +
'FROM dbo.SomeTable ';
EXEC(#strSQL);
END
GO
Then you can execute the whole thing like so:
EXEC dbo.usp_SilentExecutionProc #silentExecution = 1;
SELECT ##ROWCOUNT;
The purpose behind doing it like this is if you need the USP to be able to return a result set in other uses or cases, but still utilize it for just the rows.
Just wanted to share my solution.
I have recently come across with a similar issue while writing a migration script and since the issue was resolved in a different way, I want to record it.
I have nearly killed my SSMS Client by running a simple while loop for 3000 times and calling a procedure.
DECLARE #counter INT
SET #counter = 10
WHILE #counter > 0
BEGIN
-- call a procedure which returns some resultset
SELECT #counter-- (simulating the effect of stored proc returning some resultset)
SET #counter = #counter - 1
END
The script result was executed using SSMS and default option on query window is set to show âResults to Gridâ[Ctrl+d shortcut].
Easy Solution:
Try setting the results to file to avoid the grid to be built and painted on the SSMS client. [CTRL+SHIFT+F keyboard shortcut to set the query results to file].
This issue is related to : stackoverflow query
Man, this is seriously a case of a computer doing what you told it to do instead of what you wanted it to do.
If you don't want it to return results, then don't ask it to return results. Refactor that stored procedure into two:
CREATE PROCEDURE [dbo].[insertSomeData] (#myParam int) AS
BEGIN
DECLARE #reply varchar(2048)
--... Do a bunch of inserts/updates...
EXEC SelectOutput
END
GO
CREATE PROCEDURE SelectOutput AS
BEGIN
SET #reply = '<xml><big /><outputs /></xml>'
SELECT #reply
END
From which client are you calling the stored procedure? Say it was from C#, and you're calling it like:
var com = myConnection.CreateCommand();
com.CommandText = "exec insertSomeData 1";
var read = com.ExecuteReader();
This will not yet retrieve the result from the server; you have to call Read() for that:
read.Read();
var myBigString = read[0].ToString();
So if you don't call Read, the XML won't leave the Sql Server. You can even call the procedure with ExecuteNonQuery:
var com = myConnection.CreateCommand();
com.CommandText = "exec insertSomeData 1";
com.ExecuteNonQuery();
Here the client won't even ask for the result of the select.
You could create a SQL CLR stored procedure that execs this. Should be pretty easy.
I don't know if SQL Server has an option to suppress output (I don't think it does), but the SQL Query Analyzer has an option (under results tab) to "Discard Results".
Are you running this through isql?
You said your server is crashing. What is crashing the application that consumes the output of this SQL or SQL Server itself (assuming SQL Server).
If you are using .Net Framework application to call the stored procedure then take a look at SQLCommand.ExecuteNonQuery. This just executes stored procedure with no results returned. If problem is at SQL Server level then you are going to have to do something different (i.e. change the stored procedure).
You can include in the SP a parameter to indicate if you want it to do the select or not, but of course, you need to have access and reprogram the SP.
CREATE PROCEDURE [dbo].[insertSomeData] (#myParam int, #doSelect bit=1) AS
DECLARE #reply varchar(2048)
... Do a bunch of inserts/updates...
SET #reply = '<xml><big /><outputs /></xml>'
if #doSelect = 1
SELECT #reply
GO
ever tried SET NOCOUNT ON; as an option?