I'm trying to create some means of dynamically selecting the table for a procedure to run on based on an ID sent to the database. Something like :
#TableId int
As
Declare #nameoftable varchar(50)
select #nameoftable = Nameoftable from tablelist where id = #tableid
-- returning on selected table
Select somestuff
from #nameoftable
Any ideas?
You need to use dynamic SQL
#TableId int
As
Declare #nameoftable varchar(50)
select #nameoftable = Nameoftable from tablelist where id = #tableid
-- returning on selected table
declare #sql nvarchar(1000)
set #sql = 'Select somestuff from ' + Quotename(#nameoftable)
exec(#sql)
In MS SQL Server you can use sp_executesql to execute dynamic queries. Read The Curse and Blessings of Dynamic SQL, it helped me alot.
Related
I have a problem with treating table name as variable as I need to put the results to different table each month automatically (without using any advanced procedures to make this query dynamic). Can somebody help me to modify this code and make it work?
declare #exp_dte as date;
set #exp_dte='2015-12-31';
print (#exp_dte);
declare #tab_mth as nvarchar(max);
set #tab_mth=year(#exp_dte)*100+month(#exp_dte);
print (#tab_mth);
declare #tab_name as nvarchar(max)
set #tab_name='mis_anl.dbo.BIK_' + #tab_mth
print (#tab_name);
IF OBJECT_ID (N'#tab_name', N'U') IS NOT NULL
begin
drop table #tab_name
end
select distinct
*
into #tab_name
from table_x
You have to use dynamic SQL to set name at runtime:
DECLARE #exp_dte DATE = '2015-12-31';
DECLARE #tab_name SYSNAME = '[dbo].' + QUOTENAME('BIK_' + FORMAT(#exp_dte, 'yyyyMM'));
IF OBJECT_ID (#tab_name, N'U') IS NOT NULL
BEGIN
EXEC('DROP TABLE' + #tab_name);
END
DECLARE #sql NVARCHAR(MAX) = N'SELECT DISTINCT *
INTO #tab_name
FROM table_x';
SET #sql = REPLACE(#sql, '#tab_name', #tab_name);
EXEC [dbo].[sp_executesql] #sql;
LiveDemo
Remarks:
Try to be more conscise
You could use FORMAT to get yyyyMM (SQL Server 2012+)
Always QUOTENAME generated identifiers to avoid SQL Injection attacks
I strongly recommend to read The Curse and Blessings of Dynamic SQL especially CREATE TABLE #tbl.
use dynamic sql ,you cant user table names as variables
declare #exp_dte as date;
set #exp_dte='2015-12-31';
declare #tab_mth as nvarchar(max);
set #tab_mth=year(#exp_dte)*100+month(#exp_dte);
declare #tab_name as nvarchar(max)
set #tab_name='mis_anl.dbo.BIK_' + #tab_mth
declare #sql1 nvarchar(max)
set #sql1='drop table '+#tab_name;
IF exists(select 1 from information_schema.tables where table_name=#tab_name)
begin
exec(#sql1);
end
declare #sql nvarchar(max)
set #sql='
select distinct
*
into '+#tab_name+'
from table_x'
exec (#sql)
How to pass table name dynamically to the stored procedure or a simple SQL query, then store the results in a variable?
You may looking for something like this ?
USE [master]
GO
DECLARE #sql NVARCHAR(2000)
DECLARE #TableName NVARCHAR(100) ='sys.tables'
DECLARE #RecordCount INT
SET #sql = N' SELECT #RecordCountOut = COUNT(*)
FROM ' + #TableName + ' AS t'
EXEC sp_executesql #sql, N'#RecordCountOut INT OUTPUT', #RecordCountOut = #RecordCount OUTPUT
SELECT #RecordCount
You could stored your SQL query result in this way
DECLARE #Result NVARCHAR(MAX)
SELECT #Result = COLUMN FROM TableName
however, you could use print command to check what the query return
print #Result
I need to execute below query
SELECT *, IDENTITY( int ) AS IDColumn INTO #SmootheningTable FROM #TableName
where #SmootheningTable is temporary table
and #TableName is name of table
I need to use command either EXEC or sp_executesql to execute.
If I use EXEC, I wont be able to use #SmootheningTable in later portion of my stored procedure.
And while trying sp_executesql, I am getting error stating #statement error.
How can I use sp_executesql for above given query.
Or is there any other way to execute?
this is the query I am using
DECLARE #TablePlaceHolder VARCHAR(50)='';
DECLARE #SmootheningQuery NVARCHAR(max) = 'SELECT *, IDENTITY( int ) AS IDColumn INTO #SmootheningTable FROM #TablePlaceHolder';
EXEC sp_executesql #SmootheningQuery, N'#TablePlaceHolder varchar(50)', #PlanDetailTempTableName
and i am getting below error
Must declare the table variable "#TablePlaceHolder".
Thanks in advance
There are two issues in your code:-
First : Putting the variable name inside the string, put in out like next:-
instead of this line:-
DECLARE #SmootheningQuery NVARCHAR(max) = 'SELECT *, IDENTITY( int ) AS
IDColumn INTO #SmootheningTable FROM #TablePlaceHolder';
Type this line:-
DECLARE #SmootheningQuery NVARCHAR(max) = 'SELECT *, IDENTITY( int ) AS
IDColumn INTO #SmootheningTable FROM ' + #TablePlaceHolder;
Second: Don't use local temp table within sp_executeSql,
The Local temporary table [with one hash # ] is visible in current session only, use global temporary tables instead [with two hashes ## ] are visible in all sessions,
So instead of
#SmootheningTable
Type
##SmootheningTable
Demo (All Code): -
Create table MyTable (id int , name nvarchar(100))
go
insert into MyTable values (1, 'Ahmed');
insert into MyTable values (2, 'Abdelqader');
go
declare
#TableName varchar(50),
#MyQuery nvarchar(200)
set #TableName = 'MyTable'
set #MyQuery = 'select * Into ##MYTempTable From ' + #TableName
exec sp_executesql #MyQuery
select * from ##MYTempTable
Result:-
id name
1 Ahmed
2 Abdelqader
Please Try This,
CREATE PROC usp_SmootheningTable
AS
BEGIN
SELECT *, IDENTITY( int ) AS IDColumn INTO #SmootheningTable FROM
TableName
SELECT * FROM #SmootheningTable
END
GO
Please try this out
CREATE TABLE #Temp
(
Columns
)
DECLARE #SQL NVARCHAR(MAX)
DECLARE #TableName VARCHAR(MAX)
SET #TableName = 'TableName'
SET #SQL = 'SELECT TOP 10 * FROM '+#TableName
INSERT INTO #Temp
EXEC SP_EXECUTESQL #SQL
SELECT * FROM #Temp
I want to write a stored procedure that takes #FirmId as a parameter and I will use the related table according to this parameter.
What I want to obtain (but I don't want to use) is something like that:
CREATE PROCEDURE spFirmDetailGetByFirmId
#FirmId AS INT
AS
BEGIN
IF #FirmId = 1
SELECT * FROM Firm1
ELSE IF #FirmId = 2
SELECT * FROM Firm2
.
.
.
.
ELSE IF #FirmId = 1000
SELECT * FROM Firm1000
END
And also I don't want to create query string and then EXEC it, something like that in the fallowing code block. Because the real query is too complex and it will be very hard to manage if I use this option.
CREATE PROCEDURE spFirmDetailGetByFirmId
#FirmId AS INT
AS
BEGIN
DECLARE #Query AS NVARCHAR(MAX) = 'SELECT * FROM Firm'
SET #Query = #Query + CAST(#FirmId AS NVARCHAR(10))
EXEC(#Query)
END
Is there any other option?
Thanks.
I take your Yes the tables are identical and will be kept identical to suggest two approaches:
DECLARE #Firm VARCHAR(10)='Firm3';
SELECT * FROM Firm1 WHERE #Firm='Firm1'
UNION ALL
SELECT * FROM Firm2 WHERE #Firm='Firm2'
UNION ALL
SELECT * FROM Firm3 WHERE #Firm='Firm3'
[...]
UNION ALL
SELECT * FROM Firm1000 WHERE #Firm='Firm1000'
The second is:
DECLARE #query NVARCHAR(MAX)='SELECT * FROM ####';
SET #query=REPLACE(#query,'####',#Firm);
EXEC (#query)
The second could be used with a VIEW (in place of the #query), where you could read the VIEW's definition into the variable and create an ALTER VIEW-statement dynamically... Your procedure would call the same VIEW (but this would crash with parallel calls!)
This code can by use in a stored procedure to automatic create the view, every time you need to add columns
declare #tableId int
declare #columns varchar(max)
declare #tablesCount int
declare #tableName varchar(255)
declare #query varchar(255)
declare #id int
declare #result nvarchar(max)
set #columns = ''
set #tableName = 'Firm'
set #id = 1
set #result = ''
--Base table
select #tableId = object_id from sys.tables where name =#tableName
--Count how many table with the 'same name'
select #tablesCount= count(*) from sys.tables where name like #tableName+'%'
--Build Columns to add in the view
select #columns =#columns+name+', 'from Sys.columns where object_id = #tableId
--Drop View
set #result = 'Drop view vw_'+#tableName
exec sp_executesql #result
set #result=''
while(#id<=#tablesCount)
Begin
declare #idVarchar varchar(10)
set #idVarchar = cast(#id as varchar(10))
set #result =#result+'Select '+#columns+#idVarchar+' as FirmId from '+#tableName+#idVarchar
+'
Union all
'
set #id =#id+1
End
set #result = substring(#result, 1, len(#result)-12)
set #result='Create view vw_'+#tableName+' as
'+#result
exec sp_executesql #result
There is a another choice to this, you can also use sp_helpText to get the current definition of the view and append only add new table identifier
Why the following SQL does not fetch me anything
DECLARE #Status AS VARCHAR(400)
SET #status = '''Closed'',''OPEN'''
select * from MYTABLE where status in(#status)
While as
select * from MYTABLE where status in('Closed','Open') fetches me rows
You can if you want do some dynamic SQL but I think it is not really competitive..
DECLARE #Status nVARCHAR(400),
#SQL nvarchar(500)
SET #status = '''Closed'''+','+'''OPEN'''
set #SQL = '
select * from [MYTABLE] where status in('+#status +')'
exec sp_executesql #SQL
GO
Your first question checks if the value 'Closed','OPEN' exists in the database. The values is not expanded.
If you use SQL Server 2008 or later you can use Table Valued Parameters to achieve the same thing.