I am currently moving a SAS process to SQL. Within the SAS process, I leverage macros to create a multitude of tables.
I am trying to leverage the CREATE FUNCTION function within SQL to mimic this process, however I am stuck. I have three arguments, the server name, the name of the new table and the table where it should select from. I'm not sure what I should specify as what I am returning as I'm not looking to return anything, just create tables.
CREATE FUNCTION dbo.functionname (#server VARCHAR(250), #name VARCHAR(250), #table VARCHAR(250))
RETURN (???)
AS BEGIN
SELECT *
INTO #server.dbo.#nm
FROM #table
RETURN
END
This is what I have come up with so far. My SELECT statement wouldn't actually be *, I just put that for simplicity sake for this question.
UPDATE: In this instance, using a stored procedure is not an option as permissions have been limited.
You can create a dynamic SQL script as follows
declare #newtable sysname = 'T003',
#sourcetable sysname = 'sys.tables'
declare #sql nvarchar(max)
set #sql = N'select * into ' + #newtable + ' from ' + #sourcetable + ';'
set #sql = #sql + N'select * from ' + #newtable
exec sp_executesql #sql
Then you can use it in a stored procedure
To return data from new table, the table type must be known before. In this case it is not possible, so developer cannot create the function return type
Or create a function just to create the table and insert data into it. But return fail or success, etc
Then select from the new table using a dynamic SQL again
Related
I want to pass the table name as a parameter to table_valued function in MS SQL Server
CREATE FUNCTION maxid
(
-- Add the parameters for the function here
#tblname sysname,
#feild nvarchar(max),
)
RETURNS TABLE
AS
RETURN
(
-- Add the SELECT statement with parameter references here
select ISNULL(max(#feild),0)+1 from #tblname
)
You cannot use dynamic SQL in table valued or any other TSQL function. However, the code you provide seems to be used to obtain the next value of some identifier or counter field. The way you want to do it is highly deprecated and leads to concurrency problems.
Indeed, SQL Server can do it using at least two standard methods:
using a sequences
creating an identity column
I have done it but with store procedure
CREATE procedure [dbo].[get_maxid]
#tblname nvarchar(max),
#col nvarchar(max)
as
Begin
declare #sql nvarchar(max);
set #sql='select ISNULL(MAX('+#col+'),0)+1 as id from '+ QUOTENAME( #tblname)
execute sp_executesql #sql
End
Now Execute Store Procedure
exec get_maxid #col='col_name',#tblname='tbl_name'
I have a procedure in which there are calculations being done and the final result is inserted into a permanent table. I want to remove the permanent table and I cannot use Temp table as well. So i want to use a dynamic table name, which is stored in a variable:
Current scenario:
Insert into xyz_table
Select col1,col2,sum(col3)
from BaseTable
(In reality, there are lot of columns and a lot of calculations)
What I want:
Select col1,col2,sum(col3) into #DynamicTableName
from BaseTable
where the name of the table would be dynamic in nature i.e.,
#DynamicTableName = 'xyz ' + cast(convert(date,getdate()) as nvarchar)+' '+convert(nvarchar(5),getdate(),108)
It will have date and time in its name every time the procedure is run.
I want to use this name in the "Select * into statement"
How can I achieve this?
i tried it with the some short code. But since my procedure has a lot of calculations and UNIONS , I cannot use that code for this. Any help would be appreciated.
declare #tablename nvarchar(30)= 'xyz ' + cast(convert(date,getdate()) as nvarchar)+' '+convert(nvarchar(5),getdate(),108)
declare #SQL_Statement nvarchar(100)
declare #SQL_Statement2 nvarchar(100)
declare #dropstatement nvarchar(100)
SET #SQL_Statement = N'SELECT * Into ' +'['+#tablename +'] '+'FROM '+ 'dimBranch'
print #SQL_Statement
EXECUTE sp_executesql #SQL_Statement
SET #SQL_Statement= N'select * from ' + '['+#tablename + '] '
print #SQL_Statement
EXECUTE sp_executesql #SQL_Statement
set #dropstatement = 'DROP TABLE' + '['+#tablename + '] '
PRINT #dropstatement
exec sp_executesql #dropstatement
Reason why I want this is because I use this procedure in ETL job as well as in SSRS report. And if someone runs the package and the SSRS report at the same time, the incorrect or weird data gets stored in the table. Therefore I need a dynamic name of the table with date and time.
You can't parameterize an identifier in SQL, only a value
--yes
select * from table where column = #value
--no
select * from #tablename where #columnname = #value
The only thin you can do to make these things dynamic is to build an sql string and execute it dynamically, but your code is already doing this with sp_executesql
More telling is your complaint at the bottom of your question, that if the procedure is invoked simultaneously it gives problems. Perhaps you should consider using local table variables for temporary data storage that the report is using rather than pushing data back into the db
DECLARE #temp TABLE(id INT, name varchar100);
INSERT INTO #temp SELECT personid, firstname FROM person;
-- work with temp data
select count(*) from #temp;
--when #temp goes out of scope it is lost,
--no other procedure invoked simultaneously can access this procedure'a #temp
Consider a local temp table, which is automatically session scoped without the need for dynamic SQL. For example:
SELECT *
INTO #YourTempTable
FROM dimBranch;
The local temp table will automatically be dropped when the proc completes so there is no need for an explict drop in the proc code.
I'm inserting data into a temp table and querying the temp table fails
DECLARE #SQLQuery AS NVARCHAR(500)
SET #SQLQuery = 'SELECT Top 100 *
INTO #tempTable
FROM ' + #origDB + '.dbo.' + #origTable + ' o WITH (NOLOCK) '
EXECUTE sp_executesql #SQLQuery
and when I try to query the temp table , like so
select * from #tempTable
I get the following error :
Invalid object name '#tempTable'.
Courtesy of MSDN
The problem that you have is with the scope. The TEMP table is creatd at the scope of the EXEC() method and hence it is not available after the function returns. To fix this, create your temp table before calling EXEC() and use an INSERT INTO instead of SELECT INTO.
As others have said, the scope of a temporary table is limited to the session context in which it is created - a stored procedure runs in its own context.
You could use a global temporary table ##tempTable, but it's generally a bad idea as it would be available to other sessions than the one creating it.
I want to create a SQL tabled-value function that will receive a query as n parameter through my API. In my function I want execute that query. The query will be a SELECT statement.
This is what I have done so far and what to achieve but it is not the correct way to do so.
CREATE FUNCTION CUSTOM_EXPORT_RESULTS (
#query varchar(max),
#guid uniqueidentifier,
#tableName varchar(200))
RETURNS TABLE
AS
RETURN
(
-- Execute query into a table
SELECT *
INTO #tableName
FROM (
EXEC(#query)
)
)
GO
Please suggest the correct way!
Try this one -
CREATE PROCEDURE dbo.sp_CUSTOM_EXPORT_RESULTS
#query NVARCHAR(MAX) = 'SELECT * FROM dbo.test'
, #guid UNIQUEIDENTIFIER
, #tableName VARCHAR(200) = 'test2'
AS BEGIN
SELECT #query =
REPLACE(#query,
'FROM',
'INTO [' + #tableName + '] FROM')
DECLARE #SQL NVARCHAR(MAX)
SELECT #SQL = '
IF OBJECT_ID (N''' + #tableName + ''') IS NOT NULL
DROP TABLE [' + #tableName + ']
' + #query
PRINT #SQL
EXEC sys.sp_executesql #SQL
RETURN 0
END
GO
Output -
IF OBJECT_ID (N'test2') IS NOT NULL
DROP TABLE [test2]
SELECT * INTO [test2] FROM dbo.test
What I see in your question is encapsulation of:
taking a dynamic SQL expression
executing it to fill a parametrized table
Why do you want to have such an encapsulation?
First, this can have a negative impact on your database performance. Please read this on EXEC() and sp_executesql() . I hope your SP won't be called from multiple parts of your application, because this WILL get you into trouble, at least performance-wise.
Another thing is - how and where are you constructing your SQL? Obviously you do it somewhere else and it seems its manually created. If we're talking about a contemporary application, there are lot of OR/M solutions for this and manual construction of TSQL in runtime should be always avoided if possible. Not to mention EXEC is not guarding you against any form of SQL injection attacks. However, if all of this is a part of some database administration TSQL bundle, forget his paragraph.
At the end, if you want to simply load a new table from some existing table (or part of it) as a part of some administration task in TSQL, consider issuing a SELECT ... INTO ... This will create a new target table structure for you (omitting indexes and constraints) and copy the data. SELECT INTO will outperform INSERT INTO SELECT because SELECT INTO gets minimally logged.
I hope this will get you (and others) at least a bit on the right track.
You can use stored procedure as well, here is the code that you can try.
CREATE FUNCTION CUSTOM_EXPORT_RESULTS
(
#query varchar(max),
#guid uniqueidentifier,
#tableName varchar(200)
)
RETURNS TABLE
AS
RETURN
(
declare #strQuery nvarchar(max)
-- Execute query into a table
SET #strQuery = REPLACE(#query,'FROM', 'INTO '+#tableName+' FROM')
exec sp_executesql #strQuery
)
GO
I am writing a function that returns a table. There are two parameters that are passed to the function and a query is built and executed and inserted into the returning table. However I am receiving this error.
Only functions and some extended stored procedures can be executed from within a function.
I would like to not use a stored procedure as this is a simple utility function. Does anyone know if this can be done. My function is coded below, it checks for dupes for a certain column within a certain table.
-- =============================================
-- AUTHOR: JON AIREY
-- THIS FUNCTION WILL RETURN A COUNT OF HOW MANY
-- TIMES A CERTAIN COLUMN VALUE APPEARS IN A
-- TABLE. THIS IS HELPFUL FOR FINDING DUPES.
-- THIS FUNCTION WILL ACCEPT A COLUMN NAME, TABLE
-- NAME (MUST INCLUDE SCHEMA), AND OPTIONAL
-- DATABASE TO USE. RESULTS WILL BE RETURNED AS
-- A TABLE.
-- =============================================
ALTER FUNCTION [dbo].[fn_FindDupe]
(
-- Add the parameters for the function here
#Column VARCHAR(MAX),
#Table VARCHAR(100),
#Database VARCHAR(100) = ''
)
RETURNS
#TempTable TABLE
([Column] varchar(100)
,[Count] int)
AS
BEGIN
DECLARE #SQL VARCHAR(MAX)
SET #Table = CASE
WHEN #Database = ''
THEN #Table
ELSE #Database + '.' + #Table
END
SET #SQL =
'
INSERT INTO #TempTable
SELECT ' + #Column + '
,COUNT(' + #Column + ') AS CNT
FROM ' + #Table + '
GROUP BY ' + #Column + '
ORDER BY CNT DESC
'
EXEC SP_EXECUTESQL #SQL
RETURN
END
GO
You can't use dynamic sql in a udf:
This very simple: you cannot use dynamic SQL from used-defined
functions written in T-SQL. This is because you are not permitted do
anything in a UDF that could change the database state (as the UDF may
be invoked as part of a query). Since you can do anything from dynamic
SQL, including updates, it is obvious why dynamic SQL is not
permitted.
...
In SQL 2005 and later, you could implement your function as a CLR
function. Recall that all data access from the CLR is dynamic SQL.
(You are safe-guarded, so that if you perform an update operation from
your function, you will get caught.) A word of warning though: data
access from scalar UDFs can often give performance problems.