conditionally executing sql statement

I need to write .sql file in a dynamic way.
inside the file i need to decide at run time (of the sql script) whether or
not to run a SQL statement that I don't know it's content while dynamically
creating the sql script, this sql statement might include a GO statement
what makes a problem putting it inside an if begin end block.
for example
in my script a runtime check
select @.runStatement = configVal from database at script runtime execution
if @.runStatement =1
begin
-- here comes an unknown sql statement at the time of creating the sql
script that might include a GO command which will break the syntax of the
entire block
-- go <- this here makes a TSQL error for the end command since it
breaks the begin / end block.
end
can someone recomend of an approach for how to solve this?
execute sql is not an option here since the internal SQL statement might be
larget then 4000 nvarchar characters and I can not declarae a @.ntext local
variable
TIA.>> inside the file i need to decide at run time (of the sql script) whether
Under normal circumstances, this is a poor way to write SQL code. The kludgy
workaround is to assign the SQL statement to a variable, replace the tokens
that are not needed and use EXEC or sp_ExecuteSQL to execute it.
The right way can be suggested only if you can explain the overall
situation. Why do you have to resort to such complex approach? Is there a
3rd party tool involved?
Anith|||martin (news.microsoft.com) writes:
> I need to write .sql file in a dynamic way.
> inside the file i need to decide at run time (of the sql script) whether
> or not to run a SQL statement that I don't know it's content while
> dynamically creating the sql script, this sql statement might include a
> GO statement what makes a problem putting it inside an if begin end
> block.
> for example
> in my script a runtime check
> select @.runStatement = configVal from database at script runtime execution
> if @.runStatement =1
> begin
> -- here comes an unknown sql statement at the time of creating the
> sql script that might include a GO command which will break the syntax
> of the entire block
> -- go <- this here makes a TSQL error for the end command since it
> breaks the begin / end block.
> end
>
> can someone recomend of an approach for how to solve this?
> execute sql is not an option here since the internal SQL statement might
> be larget then 4000 nvarchar characters and I can not declarae a @.ntext
> local variable
Are you on SQL 2000 or SQL 2005?
If you are on SQL 2000, I would srtongly recommend that you run the
control loop from a client. It could be very difficult to sort out
from SQL only. It could be a little easier on SQL 2005, since there
you can work with nvarchar(MAX) and you could do the batch splitting
in CLR code.
I echoes Aniths suggestion that you could be better served by telling
us the full story. This could give you better suggestions.
Erland Sommarskog, SQL Server MVP, esquel@.sommarskog.se
Books Online for SQL Server 2005 at
http://www.microsoft.com/technet/pr...oads/books.mspx
Books Online for SQL Server 2000 at
http://www.microsoft.com/sql/prodin...ions/books.mspx|||it should support database modifications / upgrades.
the commands are not known at the time of designing the tool that will
execute the statements.
i understand that running each script from a client tool like a VB.NET app
is a good option but is it not possible to run it from sql script file using
some goto label....?
"Anith Sen" <anith@.bizdatasolutions.com> wrote in message
news:eedlU0VaGHA.1020@.TK2MSFTNGP02.phx.gbl...
> Under normal circumstances, this is a poor way to write SQL code. The
> kludgy workaround is to assign the SQL statement to a variable, replace
> the tokens that are not needed and use EXEC or sp_ExecuteSQL to execute
> it.
>
> The right way can be suggested only if you can explain the overall
> situation. Why do you have to resort to such complex approach? Is there a
> 3rd party tool involved?
> --
> Anith
>|||martin (news.microsoft.com) writes:
> it should support database modifications / upgrades.
> the commands are not known at the time of designing the tool that will
> execute the statements.
> i understand that running each script from a client tool like a VB.NET
> app is a good option but is it not possible to run it from sql script
> file using some goto label....?
Possible and possible. With severe kludges maybe. And it depends on the SQL
Server version.
If the purpose of the tool is run scripts for database changes, I strongly
recommend using a control part in a client language.
Erland Sommarskog, SQL Server MVP, esquel@.sommarskog.se
Books Online for SQL Server 2005 at
http://www.microsoft.com/technet/pr...oads/books.mspx
Books Online for SQL Server 2000 at
http://www.microsoft.com/sql/prodin...ions/books.mspxsqlsql

Conditionally CREATE a VIEW in a script

Hi,

I would like to create a view depending on a condition check first. However, I do not seem to the able to put a 'CREATE VIEW' within an IF statement. The following example demonstates what I am trying to achieve (please excuse the triviality of the example):

IF NOT col_length('authors','city') IS NULL

BEGIN
CREATE VIEW TestView
AS
SELECT (au_fname + ' ' + au_lname) as fullName, (address + ', ' + city) as fullAddress
FROM authors
END
ELSE
BEGIN
CREATE VIEW TestView
AS
SELECT (au_fname + ' ' + au_lname) as fullName, (address) as fullAddress
FROM authors
END

When I try to parse/run this I get the following syntax error:

"Incorrect syntax near the keyword 'VIEW'."

Any help would be much appreciated.

Thanks.

Try the code below.

Chris

Code Snippet

DECLARE @.sqlstring NVARCHAR(4000)

IF NOT col_length('authors', 'city') IS NULL
BEGIN
SET @.sqlstring = '
CREATE VIEW TestView
AS
SELECT (au_fname + '' '' + au_lname) as fullName, (address + '', '' + city) as fullAddress
FROM authors'
EXEC (@.sqlstring)
END
ELSE
BEGIN
SET @.sqlstring = '
CREATE VIEW TestView
AS
SELECT (au_fname + '' '' + au_lname) as fullName, (address) as fullAddress
FROM authors'
EXEC (@.sqlstring)
END

|||

I think this looks misguided. Rather than changing the view that is is created dynamically, I think you need to change the view permanently so that both views can be represented by a singular view that uses CASE construct. Hang on and if I don't get you an example, I imagine someone else will.

Maybe something like this:

create view testView
as

select au_fname + ' ' + au_lname
as fullName,
address
+ case when len(rtrim(city)) = 0
then ''
else ', ' + city
end
as address
from authors

go

select * from testView

/*
fullName address
--
Johnson White 10932 Bigge Rd., Menlo Park
Marjorie Green 309 63rd St. #411, Oakland
Cheryl Carson 589 Darwin Ln., Berkeley
*/

|||

Hi Chris,

I had thought about doing that but the real view is quite large and I was trying to avoid dealing with string manipulation but I suppose its just two single quotes for ant existing single quotes.

Thanks.

Smoc

|||

Hi Kent,

Thanks for the response but that will not work if the column does not exist in the table which is the reason I want to conditionally create 1 of 2 possible views. In the simplistic example, I want to handle the situation when the column 'city' may not be in the authors table.

I realise that i could use the col_length function instead to achieve the result you have proposed. I was just wondering why I could have two 'clean' view definitions in a script contained within an IF statement.

Regards,

Smoc

|||

Just thinking out loud really, but could you programatically add the City column to the authors table if the column doesn't exist? That way, going forward, you'd only have one version of the View to maintain.

Chris

|||

Hi Chris,

We have an application that is using a database that we have no control over and no authority to change. We have discovered some differences between schemas of different clients who have this database. The differences are not critical and we hope to handle it at the view level. Other than that we would do as you suggested.

I'm just supprised that I can do a DROP command but not a Create View command in an IF statement.

Smoc

|||

You can't create view/procedure/function/trigger inside or mid of your batch.

These create scripts should be the first line of the batch.

In IF batch you can put only the Drop view/procedure/function/trigger.

The only possible way is using dynmaic sql.

|||

Thanks for the clarification.

I will probably use the dynamic sql that you have suggested and as was also suggested in an earlier thread.

Thanks.

|||There is a neat trick to achieve just what you want . Check out this example:

-- If column doesn't exists, does not create the view that use it
IF col_length('authors','city') IS NULL set noexec on
go
CREATE VIEW dbo.TestView
AS
SELECT (au_fname + ' ' + au_lname) as fullName, (address + ', ' + city) as fullAddress
FROM authors
go
-- Return execute mode to default
set noexec off
go
-- If column exists, does not create the view without it
IF col_length('authors','city') IS not NULL set noexec on
go
CREATE VIEW dbo.TestView
AS
SELECT (au_fname + ' ' + au_lname) as fullName, (address) as fullAddress
FROM authors
go
-- Return execute mode to default
set noexec off

You only need to carefully choose your conditions because they have to be "reversed", in a way. Still, it is a proven and reliable approach.

Conditional Where wildcard problem

Hi,

I have a problem using the LIKE operator in a stored procedure. I have simplified the script so that it runs in query analyser and still have the same problem. The script is:

DECLARE @.FirstName varchar (50)

SELECT @.FirstName = 'B%'

SELECT * FROM PhoneList
WHERE PhoneList.FirstName LIKE CASE @.FirstName WHEN '' THEN PhoneList.FirstName ELSE @.FirstName END

This code produces no rows in the result. However if I change the second line to:
SELECT @.FirstName = 'Ben'
Then I get all of the rows with 'Ben' as the first name. If I change it to:
SELECT @.FirstName = 'Be%'
Then I get all of the rows with three character first names beginning with 'Be'. If I change it to:
SELECT @.FirstName = 'B%%'
Then I get all of the three character first names beginning with 'B'.

I need the conditional where so that if an empty string is passed it returns every row, which works fine as it is.

The % wildcard appears to be operating the same way as the _ wildcard. Has anyone seen this before?

This is SQL Server 2k SP3 on Win2003 server.

thanks
BenHi,

maybe you could try this:

DECLARE @.FirstName varchar (50)

SELECT @.FirstName = 'B%'

SELECT * FROM PhoneList
WHERE PhoneList.FirstName LIKE @.FirstName + '%'

If @.FIrstName is an empty string the statement should return all data.

;)

Conditional Execution in the Control Flow via Script Task

Greetings.

I'm trying to conditionally execute a dataflow based on the presence of a data file. If the data file isn't present, I'd like to execute gracefully without error.

Logic is as follows:

If FileExists Then
execute dataflow
Else
exit w/o error
End If

I've got the code ready to go, but I'm not sure how to do this conditional branch logic. Right now, the code calls the Dts.Results.Success / Failure. The problem, however, is Failure is exactly that... which doesn't result in the graceful exit I'm looking for.

Anyone have any ideas?

Thanks in advance.

Here is how I would do that:

Create a script task in your control flow to check if the file exists and write that result into a SSIS variable, let's say FileExists=1 -->exists; FileExtis=0 -->Does not exist. Then create a precedence constraint from the script task to the data flow. Then Edit the precedence constraint to use evaluation operation 'Expression and constraint'; Value 'success' and write the expression like @.[User::FileExists]==1.

This way the dataflow will be executed only if the sript task succed and the value of the variable FileExists is equal to one.

Rafael Salas

|||This sounds like a fantastic suggestion for the File System Task. I would suggest you submit it at the Microsoft Connect site.|||

Phil Brammer wrote:

This sounds like a fantastic suggestion for the File System Task. I would suggest you submit it at the Microsoft Connect site.

You mean to have a 'Check if file exists' operation in the file system task?

Rafael Salas

|||

Rafael Salas wrote:

Phil Brammer wrote:

This sounds like a fantastic suggestion for the File System Task. I would suggest you submit it at the Microsoft Connect site.

You mean to have a 'Check if file exists' operation in the file system task?

Rafael Salas

Indeed.|||

Good Idea. I followed your suggestion; for those interested in voting on that suggestion:

https://connect.microsoft.com/SQLServer/feedback/ViewFeedback.aspx?FeedbackID=231838

Rafael Salas

|||For those curious.. I documented the steps for future peoples that landed on this thread.

dichotic.wordpress.com

condition in script

hi

I need to alter a procedure depend on some information .

if A is true then

alter procedure .... < code 1>

else

alter procedure .... <code 2>

is it possible?

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=1557658&SiteID=1

Check out my post in there.

Concerning .net and SQL Procedures

Recently i had to write a script in sql to compare multiple tables to get a result of items that do not conform to certain business logic. In doing so i wrote all of this information into a sql parameter which branches out to a few other parameters within the parameter.

Now if you need the code just let me ask, but this is a general question to see if it has occured for anyone else.

The problem i am recieving is when i access the code from a .net windows application it tells me:

Error Message:
Insert Error: Column name or number of supplied values does not match table definition.
Insert Error: Column name or number of supplied values does not match table definition.

Procedure Errored On: val_GetDuplicateItemsFromAssignment
Line Number: 16

However when i run the sql parameter within SQL it accesses it just find. This is using the same parameter values.

Does anyone know why this could be happening?

Please do show the code used to insert the values.