I am having trouble with my SQL stored procedure, specifically passing in VARCHAR() as a table name using it.
My code (not working) is:
CREATE PROCEDURE DeleteUser
#Username VARCHAR(50)
AS
BEGIN
--DROP THE SURF TABLE
IF EXISTS (SELECT 1
FROM sysobjects
WHERE xtype='u' AND name=#Username + '_table')
DROP TABLE #Username + '_table'
END
GO
However, on execution it errors at the DROP TABLE #Username + '_table' line.
What could I be doing incorrectly?
I am using MS SQL Server 2008 if it matters, called from C#.
The DROP TABLE statement can't be parametrised as you are trying. You would need dynamic SQL.
DECLARE #DynSql nvarchar(max) = 'DROP TABLE ' + QUOTENAME(#Username + '_table');
EXEC(#DynSql);
Related
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 am using SQL Server 2017 and I would like to create a stored procedure with a single table name as an input variable. All I want the procedure to do is update that table in a variety of ways. This project will be done twice a year, and the columns will always be the same, so I would like to try this as a stored procedure, so I do not have to highlight several lines of code and executing each time.
Is there a simple way to pass a table name through a stored procedure which updates the table (adding columns, calculating columns, replacing nulls in columns etc). In a basic example, one task would be just replaces nulls with 0s in a column. I am not sure how to set this up though. DO I have to declare every column in the table too?
CREATE PROCEDURE updteleform
#tablename TABLE
AS
BEGIN
UPDATE #tablename
SET Recog = 0
WHERE Recog IS NULL
END
GO
I'm assuming you want to update a physical table. SQL Server table variables don't work that way, rather they are a way to pass a transient result set to a stored procedure. There is no persistence if your stored procedure does not do so.
If you are looking to update the same table, then just write the procedure to work on that table.
If you are looking to update multiple tables using the same script then you should change your procedure to accept a string parameter that would be the name of the table you want it to work on and then use dynamic SQL in your stored procedure.
Something like
CREATE PROCEDURE updteleform #tablename sysname
AS
BEGIN
DECLARE #sql NVARCHAR(MAX);
SET #sql = N'
update ' + QUOTENAME(#tablename) + '
set Recog= 0
where Recog is null;';
EXEC sp_executesql #sql;
END
GO
And then call it with something like:
EXEC updteleform #tablename = 'table1';
EXEC updteleform #tablename = 'table2';
EXEC updteleform #tablename = 'table3';
...
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
I have the following procedure:
CREATE PROCEDURE [dbo].[Test1]
AS
BEGIN
INSERT INTO [My_Database].[My_Schema].[My_Table]
(...lists columns...)
SELECT ... lots of columns from joined query...
END
Instead of hardcoding "[My_Database].[My_Schema]", I now want to select it as a variable from a predefined table like this:
CREATE PROCEDURE [dbo].[Test1]
AS
BEGIN
SELECT #myDB = [My_DB] FROM [my_custom_table]
--INSERT INTO [My_Database].[My_Schema].[My_Table]
INSERT INTO #myDB.[My_Table]
(...lists columns...)
SELECT ... lots of columns from joined query...
END
It does not work if I use it like above. I need to use:
EXEC sp_executesql (entire_sql_statement_in_quotes)
My problem is that I have a lot of these procedures to change to using a variable instead of being hardcoded. It will take forever to convert each statement to a long string.
Is there some other way to do it? What am I missing?
Regards
One idea, you could drop and recreate a synonym using dynamic SQL at the beginning of each procedure, then you can leave each Insert statement as Insert Into MySynonym
DROP SYNONYM MySynonym -- Must create it first before running this bit!
DECLARE #sql nvarchar(max)
SET #SQL = 'CREATE SYNONYM MySynonym
FOR ' + #myDB + '.test1'
EXEC sp_Executesql #sql
INSERT INTO MySynonym
SELECT ...
This would give you a peice of code you could copy paste into each SP. If the table you are inserting into is different for each SP, you could declare that too and build it into your CREATE SYNONYM statement
SET #SQL = 'CREATE SYNONYM MySynonym
FOR ' + #myDB + '.' + #MyTable
to Truncate each table first you would need to use DynamicSQL also, as you cannot delete on a synonym
SET #SQL = 'Truncate Table ' + #MyTable
EXEC sp_Executesql #sql
My SQL is quite limited and I have a number of databases within my server, I'm wondering whether its possible to write an SQL Query to loop through a listing of table names and then alter a particular table within the database name to modify a table in that database ?
Im simply wishing to add a new column to a table called site_settings.
Does MSSQL have this ability ?
You can use the script below. It returns an alter statement for each user table (you need to change your new column type as you didn't specify it) and then executes the query.
declare #sql nvarchar(max) = ''
select #sql = #sql + 'alter table ' + name + ' add site_settings int null;'
from sys.tables where type ='U'
exec sp_executesql #sql