I have an ASP.NET website (c#) and in the code-behind I want to use the IN operator in SQL http://www.w3schools.com/sql/sql_in.asp to get data from my database.
The syntax is:
SELECT column_name(s)
FROM table_name
WHERE column_name IN (value1,value2,...)
I use a stored procedure to get data, inside this procedure I run, in the end, the select.
My question is how to build dynamically the (value1, value2, ...) part of the query? How do I send as SqlParameter(s) the values that appear in the IN operator?
The stored procedure is defined like this:
CREATE PROCEDURE [dbo].[GetAllUsers]
#ORGANIZATION_ID int = null
AS
BEGIN
SET NOCOUNT ON;
begin
SELECT *
from USERS
where ORGANIZATION_ID = #ORGANIZATION_ID
end
END
I'd like to replace the WHERE clause with something like:
WHERE ORGANIZATION in (xxxxxxxxxxxxx)
How to do this?
Thank you.
You can use dynamic sql:
CREATE PROCEDURE [dbo].[GetAllUsers]
#ORGANIZATION_ID varchar(max) = null
AS
BEGIN
declare #sql varchar(max)
#sql = 'SELECT *
from USERS
where ORGANIZATION_ID in ('+#ORGANIZATION_ID+')'
SET NOCOUNT ON;
begin
exec(#sql)
end
END
You have to change type of #ORGANIZATION_ID to varchar and run the procedure with
one id:
exec '1'
or list of ids:
exec '1,2,3,4'
Related
A database had has 4 tables that has the same columns EG. SalesJAn, SalesFeb, SalesMarch, SalesApril.
I want to run a query in SQL server or in report builder Where i can change the table name based on a selection which one of 4 tables will be queried . Eg Filter in report builder
Like this
declare #tablename varchar(50)
set #tablename = 'test'
select * from #tablename
You can create a procedure which will do a select for a given table name. This procedure could look like this:
CREATE PROCEDURE EXECUTE_SELECT
#tbl sysname
AS
BEGIN
SET NOCOUNT ON;
DECLARE #SQL NVARCHAR(MAX);
SET #SQL = N' SELECT * FROM ' + QUOTENAME(#tbl)
EXECUTE sp_executesql #SQL
END
Then you can execute this procedure for every table name you want. Please see here an example according to your description: db<>fiddle
If this doesn't help you, please point out which exactly you still need to know. Thank you.
I'm running a robot test on one of our test environments, and every night, before the test runs, I would like to dump the database, and create it again from a template.
I know that PSQL has a solution for it:
CREATE DATABASE name
[ TEMPLATE [=] template ]
Is there a way I can do this in SQL Server, and write a script for it?
You can write any kind of functionality as text and then execute it as a variable. That way you can store your template as text, where you would define the database.
declare #example nvarchar(max)
set #example = 'create database examplebase'
exec sp_executesql #example
You can use this in a stored procedure where you can set database name ect. as a parameter.
create PROCEDURE sp_recreateDB
-- Add the parameters for the stored procedure here
#databasename nvarchar(max)
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
-- Insert statements for procedure here
declare #example nvarchar(max)
SET #example = N'CREATE DATABASE ' + QUOTENAME(#Databasename) + N';'
-- ect...
exec sp_executesql #example
END
GO
I am trying to code a stored procedure in SQL that does the following
Takes 2 inputs (BatchType and "Column Name").
Searches database and gives the batchdate and the data in the column = "Column name"
Code is as give below
ALTER PROCEDURE [dbo].[chartmilldata]
-- Add the parameters for the stored procedure here
(#BatchType nvarchar (50),
#Data nvarchar(50))
AS
BEGIN
-- Insert statements for procedure here
SELECT BatchDate,#Data FROM --Database-- WHERE BatchType = #BatchType
END
I am trying to select column from the database based on operator input. But I am not getting the output. It would be great if someone can give me a direction.
You may want to build out your SELECT statement as a string then execute it using sp_executesql.
See this page for more info:
https://msdn.microsoft.com/en-us/library/ms188001.aspx
This will allow you to set your query to substitute in your column name via your variable and then execute the statement. Be sure to sanitize your inputs though!
You'd need to use dynamic SQL, HOWEVER I would not recommend this solution, I don't think there is anything I can add as to why I wouldn't recommend it that isn't explained better in Erland Sommarskog in The Curse and Blessings of Dynamic SQL.
Nonetheless, if you had to do it in a stored procedure you could use something like:
ALTER PROCEDURE [dbo].[chartmilldata]
-- Add the parameters for the stored procedure here
(#BatchType nvarchar (50),
#Data nvarchar(50))
AS
BEGIN
-- DECLARE AND SET SQL TO EXECUTE
DECLARE #SQL NVARCHAR(MAX) = N'SELECT BatchDate = NULL, ' +
QUOTENAME(#Data) + N' = NULL;';
-- CHECK COLUMN IS VALID IN THE TABLE
IF EXISTS
( SELECT 1
FROM sys.columns
WHERE name = #Data
AND object_id = OBJECT_ID('dbo.YourTable', 'U')
)
BEGIN
SET #SQL = 'SELECT BatchDate, ' + QUOTENAME(#Data) +
' FROM dbo.YourTable WHERE BatchType = #BatchType;';
END
EXECUTE sp_executesql #SQL, N'#BatchType NVARCHAR(50)', #BatchType;
END
It would probably be advisable to change your input parameter #Data to be NVARCHAR(128) (or the alias SYSNAME) though, since this is the maximum for column names.
Is it natural that SQL Server does not catch objects dependencies in stored procedures through dynamic SQL:
CREATE PROCEDURE testSp (#filter nvarchar(max)) AS
exec ('select * from testTable where 1=1 AND '+ #filter)
Here SQL Server will not detect dependency between testTable and testSp.
What kind of "advice" do you have for the DBMS? I propose it could be very "cheap query" :
CREATE PROCEDURE testSp (#filter nvarchar(max)) AS
-- cheap query like 'select top 1 #id=id from testTable'
exec ('select * from testTable where 1=1 AND '+ #filter)
So the question is which queries could be good candidates for that purpose?
P.S. Of course I expect that they all will have their minuses..
When using dynamic SQL the query parts that are tekst (between quotes) are not detected as code by the IDE or the engine until the moment they are excuted. So this answers your first question, yes it is natural.
The only way around this that I can think of is to create a view using the generated output of the dynamic sql and check if the view definition is still valid at any point you want to check if the procedure is valid.
Usually when you need to do something like this there is an earlier departure from standard methods that if handled removes the need for such silly tricks.
Example:
USE demo
GO
DECLARE #sql NVARCHAR(MAX) = '
SELECT firstname, lastname FROM dbo.employees'
DECLARE #view NVARCHAR(MAX) = '
CREATE VIEW dbo.test_view
AS ' + #sql
EXEC sp_executesql #view
BEGIN TRY
DECLARE #validation int = (SELECT TOP 1 COUNT(*) FROM demo..test_view)
EXEC sp_executesql #sql
END TRY
BEGIN CATCH
PRINT 'Dynamic SQL out of date'
END CATCH
SET NOEXEC ON
select * from testTable
SET NOEXEC OFF
do the job: code really not executed, but dependecy is declared.
For the application I work on... we're creating a custom logging system. The user can view logs and apply "Tags" to them (Just like how you can apply tags to questions here!)
In this example, I'm trying to get a list of all the Logs given a "Tag." I realize I can accomplish this by using joins... but this is also an exercise for me to learn Stored Procedures a little better :)
I have a stored procedure that looks something like this to select a log by the PK
ALTER PROCEDURE [dbo].[getLogByLogId]
-- Add the parameters for the stored procedure here
#ID int
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
-- Insert statements for procedure here
SELECT TOP 1
LOG_ID,
a.A,
a.B,
a.C
FROM dbo.LOG a
WHERE a.LOG_ID = #ID
Now I would like to call this Stored Procedure from another... something like this
ALTER PROCEDURE [dbo].[getLogsByTagName]
-- Add the parameters for the stored procedure here
#TAG nvarchar(50)
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
-- Insert statements for procedure here
SELECT TOP 1000
LOG_ID --somehow store this and execute the dbo.getLogByLogId procedure here
FROM dbo.LOG_TAG a
WHERE a.TAG = #TAG
Thanks
If you have complex logic in your logbyid SP which you are trying to avoid reproducing in multiple places in your system (choice of columns, derived columns, etc), I would recommend turning that into an inline table-valued function instead (potentially without taking the ID parameter, in which case, you can actually use an ordinary view).
Then you can either join to that ITVF/view in your other stored proc (or also make another udf) which does the search or use the OUTER APPLY functionality (not as efficient).
Inline table-valued functions are basically parameterized views and can be optimized fairly easily by the optimizer.
If you want to call another sproc from within a sproc just use:
CREATE PROCEDURE myTestProc
AS
BEGIN
--Do some work in this procedure
SELECT blah FROM foo
--now call another sproc
EXEC nameOfSecondSproc
END
The only way you can achive what you are attempting is by using a CURSOR.
If this is for your learning only, then by all means, give this a go, but I would not recomend this for production.
It would go something like this
DECLARE #Table TABLE(
ID INT
)
INSERT INTO #Table SELECT 1
INSERT INTO #Table SELECT 2
INSERT INTO #Table SELECT 3
INSERT INTO #Table SELECT 4
INSERT INTO #Table SELECT 5
INSERT INTO #Table SELECT 6
DECLARE Cur CURSOR FOR
SELECT ID
FROM #Table
OPEN Cur
DECLARE #ID INT
FETCH NEXT FROM Cur INTO #ID
WHILE ##FETCH_STATUS = 0
BEGIN
PRINT #ID
FETCH NEXT FROM Cur INTO #ID
END
CLOSE Cur
DEALLOCATE Cur
By using the #ID retrieved in the WHILE loop, you can then execute the sp you wish and insert the values into a table variable.
INSERT INTO #Table EXEC sp_MySP #ID
You can call a stored procedure from another using the following syntax:
ALTER PROCEDURE [dbo].[getLogsByTagName]
-- Add the parameters for the stored procedure here
#TAG nvarchar(50)
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
-- Insert statements for procedure here
SELECT TOP 1000
LOG_ID --somehow store this and execute the dbo.getLogByLogId procedure here
FROM dbo.LOG_TAG a
WHERE a.TAG = #TAG
-- Execute dbo.getLogByLogId stored procedure
DECLARE #logId INTEGER
SET #logId = <some value>
EXEC dbo.getLogByLogId #logId
END
However, the difficult part of your question is that your dbo.getLogByLogId procedure can only accept a single LogID parameter and therefore will only be able to return a single Log record. You need to return information for all Logs where the LogId has a corresponding record in the Tags table.
The correct way to do this would be to JOIN the Log and Tag tables together, like so:
SELECT *
FROM dbo.LOG_TAG a
INNER JOIN dbo.LOG b ON a.LOG_ID = b.LOG_ID
WHERE a.TAG = #TAG
If you are concerned about returning the same logId multiple times, you can use the DISTINCT keyword in the SELECT statement to filter out the duplicated logIds.
You may also be able to rewrite your dbo.getLogByLogId procedure as a user-defined function (UDF). UDFs can accept a table as a parameter and return a table result.
An introduction to user-defined functions can be found in this article.