We have a set of tables that have a day of week suffix (Table_Mon, Table_Tue, etc.). I am trying to come up with a design where an application can pull a limited set of data out of these columns for whatever day it is currently. I was looking at using dynamic sql in a view but that is not an option. What is the correct solution so that an application can query the tables without needing to provide the day of week?
It is a poorly designed database schema. Ideally, there should be only one table with a column Week_Day and you should be able to query that table by just adding the appropriate WHERE clause.
Anyway, you will need to use dynamic sql, but instead of a view you should use a Stored Procedure. Something like...
CREATE PROCEDURE dbo.Get_Data
AS
BEGIN
SET NOCOUNT ON;
DECLARE #Sql NVARCHAR(MAX)
,#TableName SYSNAME;
SET #TableName = N'TABLE_' + LEFT(DATENAME(WEEKDAY, GETDATE()) , 3);
SET #Sql = N' SELECT * FROM ' + QUOTENAME(#TableName)
Exec sp_executesql #Sql
END
Related
I have been researching this for a couple of days and feel like I am going around in circles. I have basic knowledge of SQL but there are many areas I do not understand.
I have a table that stores the names and fields of all the other tables in my database.
tblFields
===================================================
TableName FieldName BookmarkName
---------------------------------------------------
Customer FirstName CustomerFirstName
Customer LastName CustomerLastName
Customer DOB CustomerDOB
I want to write a SELECT statement like the following but i am unable to get it work:
SELECT (SELECT [FieldName] FROM [TableName]) FROM tblFields
Is this possible? The application I have developed requires this for user customization of reports.
If i understand what you are trying to do, i think this will help you. It is not pretty and it works for SQL Server 2005 and above, but maybe this is what you are looking for:
declare #tableName nvarchar(100)
declare #sqlQuery nvarchar(max)
declare #fields varchar(500)
set #tableName = 'YourTableName'
set #fields = ''
select #fields = #fields + QUOTENAME(t.fieldname) + ',' from (
select distinct fieldname from tblfields where tablename = #tableName)t
set #sqlQuery = 'select ' + left(#fields, LEN(#fields)-1) + ' from ' + QUOTENAME(#tableName)
execute sp_executesql #sqlQuery
Edit: As Martin suggested, i edited so that the columns and tablename are using QUOTENAME
If I understand correctly what you are trying to do, you are probably better off doing this as two separate queries from your program. One which gets the fields you want to select which you then use in your program to build up the second query which actually gets the data.
If it must be done entirely in SQL, then you will need to tell us what database you are using. If it is SQL Server, you might be able to user a cursor over the first query to build up the second query which you then execute with the sp_executesql stored procedure. But doing doing it outside of SQL would be recommended.
create proc City_Info
#StateRef nvarchar(20)
as
begin
declare #StateCod nvarchar(3);
declare #Check int;
select #StateCod = StateCod from State_Cod where State_Nam = #StateRef
create table C0NCAT(#StateCod' ,'City')(Sno int identity(1,1))
end
Can Anyone tell how can i fetch a Particular Name from Column and Make table using Procedure in mssql?
First of all it looks like classic example of SELECT * FROM sales + #yymm
This is a variation of the previous case, where there is a suite of tables that actually do describe the same entity. All tables have the same columns, and the name includes some partitioning component, typically year and sometimes also month. New tables are created as a new year/month begins.
In this case, writing one stored procedure per table is not really feasible. Not the least, because the user may want to specify a date range for a search, so even with one procedure per table you would still need a dynamic dispatcher.
If you still want to go this way you could use Dynamic-SQL.
create proc City_Info
#StateRef nvarchar(20)
as
begin
declare #StateCod nvarchar(3);
declare #Check int;
select #StateCod = StateCod from State_Cod where State_Nam = #StateRef;
DECLARE #sql NVARCHAR(MAX) =
'create table '
+ QUOTENAME(C0NCAT(#StateCod ,'City'))
+ '(Sno int identity(1,1))';
EXEC sp_executesql #sql
end
I have to create a stored procedure where I will pass tableName, columnName, id as parameters. The task is to select records from the passed table where columnName has passed id. If record is found update records with some fixed data. Also implement Transaction so that we can rollback in case of any error.
There are hundreds of table in database and each table has different schema that is why I have to pass columnName.
Don't know what is the best approach for this. I am trying select records into a temp table so that I can manipulate it as per requirement but its not working.
I am using this code:
ALTER PROCEDURE [dbo].[GetRecordsFromTable]
#tblName nvarchar(128),
#keyCol varchar(100),
#key int = 0
AS
BEGIN
SET NOCOUNT ON;
BEGIN TRY
--DROP TABLE #TempTable;
DECLARE #sqlQuery nvarchar(4000);
SET #sqlQuery = 'SELECT * FROM ' + #tblName + ' WHERE ' + #keyCol + ' = 2';
PRINT #sqlQuery;
INSERT INTO #TempTable
EXEC sp_executesql #sqlQuery,
N'#keyCol varchar(100), #key int', #keyCol, #key;
SELECT * FROM #TempTable;
END TRY
BEGIN CATCH
EXECUTE [dbo].[uspPrintError];
END CATCH;
END
I get an error
Invalid object name '#TempTable'
Also not sure if this is the best approach to get data and then update it.
If you absolutely must make that work then I think you'll have to use a global temp table. You'll need to see if it exists before running your dynamic sql and clean up. With a fixed table name you'll run into problems with other connections. Inside the dynamic sql you'll add select * into ##temptable from .... Actually I'm not even sure why you want the temp table in the first place. Can't the dynamic sql just return the results?
On the surface it seems like a solid idea to have one generic procedure for returning data with a couple of parameters to drive it but, without a lot of explanation, it's just not the way database are designed to work.
You should create the temp table.
IF OBJECT_ID('tempdb..##TempTable') IS NOT NULL
DROP TABLE ##TempTable
CREATE TABLE ##TempTable()
I have around 50 tables in my database. In all tables where there is userid column (Not all the tables contain this column), I need to change the value of it from "User1" to "User2". This query would be re-used many times with changing values of "User1" and "User2"
Probably create a stored procedure to do the same like
create procedure sp_update_table(#tbl_name varchar(30))
as
begin
DECLARE #sql AS NVARCHAR(MAX)
SET #sql = N'UPDATE ' + QUOTENAME(#tbl_name ) +
'SET userid='User2' WHERE userid='User1''
EXEC sp_executesql #sql
end
then just call your procedure as many times you want passing the table name like
exec sp_update_table('mytable')
EDIT:
You can easily find all tables which contains userid column from INFORMATION_SCHEMA.COLUMNS as below
Use [DatabaseName]
Select table_name From INFORMATION_SCHEMA.COLUMNS Where column_name = 'userid'
Write 50 update statements:
UPDATE <TABLE NAME>
SET userid='User2'
WHERE userid='User1'
It should be easy enough to generate these in a simple text editor and then paste into SQL Server Management Studio.
I am attempting to make a stored procedure that uses sp_executesql. I have looked long and hard here, but I cannot see what I am doing incorrectly in my code. I'm new to stored procedures/sql server functions in general so I'm guessing I'm missing something simple. The stored procedure alter happens fine, but when I try run it I'm getting an error.
The error says.
Msg 1087, Level 15, State 2, Line 3
Must declare the table variable "#atableName"
The procedure looks like this.
set ANSI_NULLS ON
set QUOTED_IDENTIFIER ON
go
ALTER PROCEDURE [dbo].[sp_TEST]
#tableName varchar(50),
#tableIDField varchar(50),
#tableValueField varchar(50)
AS
BEGIN
SET NOCOUNT ON;
DECLARE #SQLString nvarchar(500);
SET #SQLString = N'SELECT DISTINCT #aTableIDField FROM #atableName';
EXEC sp_executesql #SQLString,
N'#atableName varchar(50),
#atableIDField varchar(50),
#atableValueField varchar(50)',
#atableName = #tableName,
#atableIDField = #tableIDField,
#atableValueField = #tableValueField;
END
And I'm trying to call it with something like this.
EXECUTE sp_TEST 'PERSON', 'PERSON.ID', 'PERSON.VALUE'
This example isn't adding anything special, but I have a large number of views that have similar code. If I could get this stored procedure working I could get a lot of repeated code shrunk down considerably.
Thanks for your help.
Edit: I am attempting to do this for easier maintainability purposes. I have multiple views that basically have the same exact sql except the table name is different. Data is brought to the SQL server instance for reporting purposes. When I have a table containing multiple rows per person id, each containing a value, I often need them in a single cell for the users.
You can not parameterise a table name, so it will fail with #atableName
You need to concatenate the first bit with atableName, which kind defeats the purpose fo using sp_executesql
This would work but is not advisable unless you are just trying to learn and experiment.
ALTER PROCEDURE [dbo].[sp_TEST]
#tableName varchar(50),
#tableIDField varchar(50),
#tableValueField varchar(50)
AS
BEGIN
SET NOCOUNT ON;
DECLARE #SQLString nvarchar(500);
SET #SQLString = N'SELECT DISTINCT ' + quotename(#TableIDField) + ' FROM ' + quotename(#tableName);
EXEC sp_executesql #SQLString;
END
Read The Curse and Blessings of Dynamic SQL
You cannot use variables to pass table names and column names to a dynamic query as parameters. Had that been possible, we wouldn't actually have used dynamic queries for that!
Instead you should use the variables to construct the dynamic query. Like this:
SET #SQLString = N'SELECT DISTINCT ' + QUOTENAME(#TableIDField) +
' FROM ' + QUOTENAME(#TableName);
Parameters are used to pass values, typically for use in filter conditions.