1) In SQL Server I have stored procedure and it has joins with multiple tables.
2) In that, UserMaster, RoleMaster and UserType table are there
3) Role Master will have the Following roles RoleX, RoleY and RoleZ
4) In User type master we have user type values like Type1 and Type2 only for RoleZ (As per requirement)
5) Now in the user table I have n number of users, and they are associated with any one of the above roles and only for RoleZ they may associated with either one of the user type
Problem:
Now in the GUI I will get user filter with the Role and user type, and they will send more than one role for filter , if they apply filter for RoleZ then only they will give the usertype filter, how can I write a query to fetch the record for this scenario
Kindly help on this quickly
The parameters (filter conditions) must be variables and the use of dynamic query can be helpful.
For one parameter (filter condition) below is the example.
if(#param1 is not null)
then
begin
declare #var varchar(max)= 'select * from tablename where columnname = ' + #param1
exec(#var)
end
if(#param1 is not null and #param2 is not null)
then
begin
declare #var varchar(max)= 'select * from tablename where columnname1 = ' + #param1 + 'and columnname2 = ' + #param2
exec(#var)
end
necessary casting should be done based on your requirements and the assignment of #var variables should change depending on the parameters dynamically.
You can check If.. Else to keep it simple in the stored procedure.
If(#usertype is not null)
Begin
//query for user type
Else
//query for role only
End
This can get you started
https://learn.microsoft.com/en-us/sql/t-sql/language-elements/if-else-transact-sql
Related
We're trying to write some automated reports to execute SQL statements we have stored in a table. The table data is normally used in a stored procedure called by the triggers and uses data passed in via temp tables (created in the trigger statements), and has a table name, then an SQL statement that works on #TempInserted and #TempDeleted, which correspond to the Inserted and Deleted objects from the trigger and then some e-mail columns that determine where to send the output.
This all works fine from the trigger statements, as each creates each temp table once, during execution:-
SELECT * INTO #TempInserted FROM INSERTED
SELECT * INTO #TempDeleted FROM DELETED
Then the trigger calls the TriggerHandler stored procedure, passing the table name through as a pararmeter.
..
However, when I try to create these dynamically from a general stored procedure in order to fire off these statements as reports (so we don't duplicate the statements), in a batch, I'm hitting a problem:-
SELECT * INTO #TempInserted FROM ...
works fine from a defined table, or object (e.g. "FROM INSERTED"), but I've found that it can't get it's schema from a dynamic query.
For example, I can do
SELECT TOP 1 * INTO #Test FROM TableA
SELECT * FROM #Test
DROP TABLE #Test
But I can't then do
EXECUTE sp_executesql N'SELECT TOP 1 * INTO #Test FROM TableA'
SELECT * FROM #Test
DROP TABLE #Test
because then #Test is local to the EXECUTE context, and not its parent.
I can, however, do the insert in the EXECUTE (or a stored procedure) because the temp table is in scope, if I've already created the table schema:-
SELECT * INTO #Test FROM TableA WHERE 1 = 2 -- create an empty schema
EXECUTE sp_executesql N'INSERT INTO #Test SELECT TOP 10 * FROM TableA'
SELECT * FROM #Test
DROP TABLE #Test
So, that's OK, but my problem comes when I want to dynamically create that schema, depending on the table name were running the reports for. The INSERT works:-
SELECT * INTO #Test FROM TableA WHERE 1 = 2 -- create an empty schema
DECLARE #Table NVARCHAR(20) = 'TableA'
DECLARE #SQL NVARCHAR(200) = N'INSERT INTO #Test SELECT TOP 10 * FROM ' + #Table
EXECUTE sp_executesql #SQL
SELECT * FROM #Test
DROP TABLE #Test
But only if the temp table already has a schema. If I try to conditionally create the schema, depending on the table selected, I get a parsing error:-
DECLARE #Table NVARCHAR(20) = 'TableA'
IF #Table = 'TableA'
SELECT * INTO #Test FROM TableA WHERE 1 = 2 -- create an empty schema
IF #Table = 'TableB'
SELECT * INTO #Test FROM TableB WHERE 1 = 2 -- create an empty schema
DECLARE #SQL NVARCHAR(200) = N'INSERT INTO #Test SELECT TOP 10 * FROM ' + #Table
EXECUTE sp_executesql #SQL
SELECT * FROM #Test
DROP TABLE #Test
gives "There is already an object named '#Test' in the database." - so the query parser isn't following the structure of the query, which only actually creates the temp table once. This also holds true if you do
SELECT * INTO #Test FROM ....
DROP TABLE #Test
SELECT * INTO #Test FROM ....
So, is there a way in SQL Server 2012, of either being able to do
SELECT * INTO #Test FROM (dynamic SQL statement)
or to bypass the parser thinking you're creating the object twice
DECLARE #Table NVARCHAR(20) = 'TableA'
IF #Table = 'TableA'
SELECT * INTO #Test FROM TableA WHERE 1 = 2 -- create an empty schema
IF #Table = 'TableB'
SELECT * INTO #Test FROM TableB WHERE 1 = 2 -- create an empty schema
or to dynamically create the locally scoped temp table, from an existing database table's schema, where the table name is stored in a variable (all the examples I've found of this use the "SELECT * INTO #Test" code, which as I mentioned requires a statically defined object to create from)?
-------edit--------
For a bit of context, here's an example of why we're doing this:-
A trigger may fire producing a warning e-mail if a certain item type is transacted into a certain location. This works with our current triggers. The reason we're doing this is so that we can, in future, write a UI so the users can add other item types to this list themselves, rather than us having to update the trigger - this also means that we can control/validate the SQL being generated, behind the scenes of a point-and-click interface so that our users don't need to know any SQL and that we can be sure that nothing malicious or that will cause errors will be used.
We also can't do this in the BLL because it's from our ERP system and this would then mean we'd have to make changes to base objects, which is obviously undesirable if it can be avoided.
There is the potential for some of these e-mails to be missed/ignored/forgotten/not-actioned, so the users requested the same information on a periodic basis, as well as as-at the transaction occurring:-
So, next, we want to produce, for some of these trigger statements, daily/weekly/monthly reports. Now, obviously, it would be ideal if we could use the existing SQL trigger statements we have set up as then if one were changed it would then automatically affect the periodical reports - stay DRY. It would also mean that if we set up a new trigger, we could automatically include it in the reports by merely inserting a reference to the trigger code, along with the table name, frequency, etc, into the table that drives the periodical reports stored procedure. Again, in future, we could then write a UI, so that users can then request and schedule these reports themselves, with no intervention required from us.
I suspect I'm stuck in a catch-22 situation here. However, I've found a way around it that isn't too messy. I extract the item processing code into another stored procedure, and then compound execution of that onto the dynamic "SELECT INTO" statement - that way it runs in the same execution instance and thus has access to the temp table created in, and local to, that instance:-
SET #SQL = 'SELECT * INTO #TestTable FROM ' + #Table + ' WHERE ' + #WhereClause
SET #SQL = #SQL + '; EXEC ReportProcess'
EXECUTE sp_executeSQL #SQL
the ReportProcess stored procedure then has access to the temporary table and can process it, accordingly
I have db A and db B. At the beginning of a stored procedure I want to back up all rows from B.mytable to B.mytablebackup. The rest of the stored procedure runs against tables on db A (which gathers data and writes it to B.mytable).
So I check to see if B.mytablebackup exists
IF EXISTS(SELECT 1 FROM B.dbo.mytablebackup)
and if it does, the stored procedure does an
INSERT INTO B..mytablebackup SELECT * FROM B..mytable
If it doesn't exist it does a
SELECT * INTO B..mytablebackup from B..mytable
But when I execute the stored procedure I get the error
There is already an object named 'mytablebackup' in the database
I added a Print statement and execution is taking the "does not exist" branch of the IF.
What am I doing wrong?
For SQL Server, you should use system view sys.tables to check if table exists.
IF EXISTS(SELECT 1 FROM B.sys.tables WHERE name = 'mytablebackup')
OBJECT_ID can be used too:
IF OBJECT_ID('B.dbo.mytablebackup') IS NOT NULL
You can directly check from the given DB,SCHEMA and TABLE parameters (For dynamic database, schema and table use)
DECLARE #targetdatabase NVARCHAR(MAX),
#SchemaName NVARCHAR(MAX),
#TableName NVARCHAR(MAX)
DECLARE #TempTableName NVARCHAR(MAX) = QUOTENAME(#targetdatabase) + '.' +
QUOTENAME(#SchemaName) + '.' + QUOTENAME(#TableName)
IF OBJECT_ID(#TempTableName) IS NULL
BEGIN
PRINT #TempTableName
END
I have a stored procedure which returns user Token if authentication passes like this
BEGIN
SET FMTONLY OFF --Tricky Part
DECLARE #token uniqueidentifier
DECLARE #user_id as int
SET #user_id = (SELECT UserID FROM Users
WHERE #email = Email AND #password = PasswordKey)
IF #user_id IS NOT NULL
BEGIN
SET #token = NEWID()
UPDATE Users SET Token = #token
WHERE UserID = #user_id
SELECT * FROM Users WHERE UserID = #user_id
END
END
Without SET FMTONLY OFF it returns Token BUT only if user entered correct cardinalities else error
A member of the type, 'Token', does not have a corresponding column in the data reader with the same name.
occurs.
Now I have another stored procedure (almost same as this one) which returns single Product determined by ID which I pass to the stored procedure and it works fine even when I send non-existing ones. In function import, one stored procedure shows me columns which returns and another one doesn't. For clarity here are two images which shows stored procedures and function import Images
Instead of using:
SELECT * FROM Users WHERE UserID = #user_id
List out the names of the columns that you wish to return from the Users table instead of just using SELECT *.
SELECT ColumnName,
AnotherColumn,
YouGetThePoint
FROM ...
It sounds like the DataReader is being populated with column names that are different than the expected column names. Have you stepped through with a debugger and/or listed out the actual column names that are being returned from the procedures to is if they are just being given arbitrary names (e.g. T1, T2).
Create Procedure [dbo].[spGenerateID]
(
#sFieldName NVARCHAR(100),
#sTableName NVARCHAR(100)
)
AS
BEGIN
SELECT ISNULL(MAX(ISNULL(#sFieldName, 0)), 0) + 1 FROM #sTableName
END
In the above procedure I supply the field name and table name and I want the max number of this field .Why this not work?I also want to check if those fields are null than it's not work.. This procedure must have a return parameter of the field that I supplied which contain the max number.Please help me to fixed it.
Why does this not work.
How to check input parameter are not null.
How to set output parameter
You can't have field names and table names as parameters without wrapping the entire SELECT statement in an EXEC statement:
EXEC ('select isnull(max(isnull([' + #sFieldName + '],0)),0)+1
from [' + #sTableName + '] ')
You cannot supply the tablename and fieldname as parameters to a stored procedure.
You need to create a dynamic query and execute using sp_executesql.
You should read The Curse and Blessings of Dynamic SQL
If this is always to be used for identity columns you can use a variable
SELECT ISNULL(IDENT_CURRENT(#sTableName),0)+1
Otherwise you need to use dynamic SQL (The usual caveats about SQL injection apply.)
Additionally I'm somewhat dubious about the reasons behind this anyway unless you don't have any concurrency to worry about.
I've changed the type of your parameters to sysname as this is more appropriate.
CREATE PROCEDURE [dbo].[spGenerateID]
(
#sFieldName sysname,
#sTableName sysname,
#id int output
)
AS
BEGIN
DECLARE #dynsql NVARCHAR(1000)
SET #dynsql = 'select #id =isnull(max([' + #sFieldName + ']),0)+1 from [' + #sTableName + '];'
EXEC sp_executesql #dynsql, N'#id int output', #id OUTPUT
END
Example Usage
DECLARE #id int
EXECUTE [dbo].[spGenerateID]
'id'
,'MYTABLE'
,#id OUTPUT
SELECT #id
1) This won't work because of the way the table name was passed.
2) You only have to check for ISNULL one time, you have a redundant number of calls there.
3) You need not necessarily declare an output, just catch the return value when you execute the stored procedure.
If you're trying to generate a unique Id this is not the best way to do it because you could run into race conditions and generate a duplicate ID for one of the calls. Ideally the ID is already declared as an IDENTITY column, but if you can't do it that way then it's better to create a special table that just returns an ID as an IDENTITY column. Then you can access that table to get the latest version with assurance that you will get a unique ID.
Here is how your stored procedure could work without the redundant IsNull().
Create Procedure [dbo].[spGenerateID]
#sFieldName NVARCHAR(100),
#sTableName NVARCHAR(100)
AS
BEGIN
Exec ( 'SELECT max(isnull(' + #sFieldName + ',0))+1 FROM ' + #sTableName)
END
It looks like #temptables created using dynamic SQL via the EXECUTE string method have a different scope and can't be referenced by "fixed" SQLs in the same stored procedure.
However, I can reference a temp table created by a dynamic SQL statement in a subsequence dynamic SQL but it seems that a stored procedure does not return a query result to a calling client unless the SQL is fixed.
A simple 2 table scenario:
I have 2 tables. Let's call them Orders and Items. Order has a Primary key of OrderId and Items has a Primary Key of ItemId. Items.OrderId is the foreign key to identify the parent Order. An Order can have 1 to n Items.
I want to be able to provide a very flexible "query builder" type interface to the user to allow the user to select what Items he want to see. The filter criteria can be based on fields from the Items table and/or from the parent Order table. If an Item meets the filter condition including and condition on the parent Order if one exists, the Item should be return in the query as well as the parent Order.
Usually, I suppose, most people would construct a join between the Item table and the parent Order tables. I would like to perform 2 separate queries instead. One to return all of the qualifying Items and the other to return all of the distinct parent Orders. The reason is two fold and you may or may not agree.
The first reason is that I need to query all of the columns in the parent Order table and if I did a single query to join the Orders table to the Items table, I would be repoeating the Order information multiple times. Since there are typically a large number of items per Order, I'd like to avoid this because it would result in much more data being transfered to a fat client. Instead, as mentioned, I would like to return the two tables individually in a dataset and use the two tables within to populate a custom Order and child Items client objects. (I don't know enough about LINQ or Entity Framework yet. I build my objects by hand). The second reason I would like to return two tables instead of one is because I already have another procedure that returns all of the Items for a given OrderId along with the parent Order and I would like to use the same 2-table approach so that I could reuse the client code to populate my custom Order and Client objects from the 2 datatables returned.
What I was hoping to do was this:
Construct a dynamic SQL string on the Client which joins the orders table to the Items table and filters appropriate on each table as specified by the custom filter created on the Winform fat-client app. The SQL build on the client would have looked something like this:
TempSQL = "
INSERT INTO #ItemsToQuery
OrderId, ItemsId
FROM
Orders, Items
WHERE
Orders.OrderID = Items.OrderId AND
/* Some unpredictable Order filters go here */
AND
/* Some unpredictable Items filters go here */
"
Then, I would call a stored procedure,
CREATE PROCEDURE GetItemsAndOrders(#tempSql as text)
Execute (#tempSQL) --to create the #ItemsToQuery table
SELECT * FROM Items WHERE Items.ItemId IN (SELECT ItemId FROM #ItemsToQuery)
SELECT * FROM Orders WHERE Orders.OrderId IN (SELECT DISTINCT OrderId FROM #ItemsToQuery)
The problem with this approach is that #ItemsToQuery table, since it was created by dynamic SQL, is inaccessible from the following 2 static SQLs and if I change the static SQLs to dynamic, no results are passed back to the fat client.
3 around come to mind but I'm look for a better one:
1) The first SQL could be performed by executing the dynamically constructed SQL from the client. The results could then be passed as a table to a modified version of the above stored procedure. I am familiar with passing table data as XML. If I did this, the stored proc could then insert the data into a temporary table using a static SQL that, because it was created by dynamic SQL, could then be queried without issue. (I could also investigate into passing the new Table type param instead of XML.) However, I would like to avoid passing up potentially large lists to a stored procedure.
2) I could perform all the queries from the client.
The first would be something like this:
SELECT Items.* FROM Orders, Items WHERE Order.OrderId = Items.OrderId AND (dynamic filter)
SELECT Orders.* FROM Orders, Items WHERE Order.OrderId = Items.OrderId AND (dynamic filter)
This still provides me with the ability to reuse my client sided object-population code because the Orders and Items continue to be returned in two different tables.
I have a feeling to, that I might have some options using a Table data type within my stored proc, but that is also new to me and I would appreciate a little bit of spoon feeding on that one.
If you even scanned this far in what I wrote, I am surprised, but if so, I woul dappreciate any of your thoughts on how to accomplish this best.
You first need to create your table first then it will be available in the dynamic SQL.
This works:
CREATE TABLE #temp3 (id INT)
EXEC ('insert #temp3 values(1)')
SELECT *
FROM #temp3
This will not work:
EXEC (
'create table #temp2 (id int)
insert #temp2 values(1)'
)
SELECT *
FROM #temp2
In other words:
Create temp table
Execute proc
Select from temp table
Here is complete example:
CREATE PROC prTest2 #var VARCHAR(100)
AS
EXEC (#var)
GO
CREATE TABLE #temp (id INT)
EXEC prTest2 'insert #temp values(1)'
SELECT *
FROM #temp
1st Method - Enclose multiple statements in the same Dynamic SQL Call:
DECLARE #DynamicQuery NVARCHAR(MAX)
SET #DynamicQuery = 'Select * into #temp from (select * from tablename) alias
select * from #temp
drop table #temp'
EXEC sp_executesql #DynamicQuery
2nd Method - Use Global Temp Table:
(Careful, you need to take extra care of global variable.)
IF OBJECT_ID('tempdb..##temp2') IS NULL
BEGIN
EXEC (
'create table ##temp2 (id int)
insert ##temp2 values(1)'
)
SELECT *
FROM ##temp2
END
Don't forget to delete ##temp2 object manually once your done with it:
IF (OBJECT_ID('tempdb..##temp2') IS NOT NULL)
BEGIN
DROP Table ##temp2
END
Note: Don't use this method 2 if you don't know the full structure on database.
I had the same issue that #Muflix mentioned. When you don't know the columns being returned, or they are being generated dynamically, what I've done is create a global table with a unique id, then delete it when I'm done with it, this looks something like what's shown below:
DECLARE #DynamicSQL NVARCHAR(MAX)
DECLARE #DynamicTable VARCHAR(255) = 'DynamicTempTable_' + CONVERT(VARCHAR(36), NEWID())
DECLARE #DynamicColumns NVARCHAR(MAX)
--Get "#DynamicColumns", example: SET #DynamicColumns = '[Column1], [Column2]'
SET #DynamicSQL = 'SELECT ' + #DynamicColumns + ' INTO [##' + #DynamicTable + ']' +
' FROM [dbo].[TableXYZ]'
EXEC sp_executesql #DynamicSQL
SET #DynamicSQL = 'IF OBJECT_ID(''tempdb..##' + #DynamicTable + ''' , ''U'') IS NOT NULL ' +
' BEGIN DROP TABLE [##' + #DynamicTable + '] END'
EXEC sp_executesql #DynamicSQL
Certainly not the best solution, but this seems to work for me.
I would strongly suggest you have a read through http://www.sommarskog.se/arrays-in-sql-2005.html
Personally I like the approach of passing a comma delimited text list, then parsing it with text to table function and joining to it. The temp table approach can work if you create it first in the connection. But it feel a bit messier.
Result sets from dynamic SQL are returned to the client. I have done this quite a lot.
You're right about issues with sharing data through temp tables and variables and things like that between the SQL and the dynamic SQL it generates.
I think in trying to get your temp table working, you have probably got some things confused, because you can definitely get data from a SP which executes dynamic SQL:
USE SandBox
GO
CREATE PROCEDURE usp_DynTest(#table_type AS VARCHAR(255))
AS
BEGIN
DECLARE #sql AS VARCHAR(MAX) = 'SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE = ''' + #table_type + ''''
EXEC (#sql)
END
GO
EXEC usp_DynTest 'BASE TABLE'
GO
EXEC usp_DynTest 'VIEW'
GO
DROP PROCEDURE usp_DynTest
GO
Also:
USE SandBox
GO
CREATE PROCEDURE usp_DynTest(#table_type AS VARCHAR(255))
AS
BEGIN
DECLARE #sql AS VARCHAR(MAX) = 'SELECT * INTO #temp FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE = ''' + #table_type + '''; SELECT * FROM #temp;'
EXEC (#sql)
END
GO
EXEC usp_DynTest 'BASE TABLE'
GO
EXEC usp_DynTest 'VIEW'
GO
DROP PROCEDURE usp_DynTest
GO