I have a table which gets created Dynamically every 1st of a month. something like test201711 for November.
I want to check if test201711 exists in the DB Drop test201711
What I tried so far:
Declare #ste varchar(max)
set #ste = 'if exists (select * from INFORMATION_SCHEMA.TABLES where TABLE_NAME =''test'+CONVERT(varchar(6),getdate(),112) + ''');' + ' Drop table test'+ CONVERT(varchar(6),getdate(),112)
print #ste
exec(#ste)
When I am printing the query it is correct, but when I am executing it is giving me an error.
What is wrong with my code here??
Simply use like this. It works for me.
-- Create the table for testing
CREATE TABLE Test201711
(
id INT
)
SELECT NAME
FROM sys.tables AS t
WHERE t.name = 'Test201711'
DECLARE #TableName VARCHAR(100) = 'Test' + CONVERT(VARCHAR(6), GETDATE(), 112)
IF OBJECT_ID(#TableName) IS NOT NULL
EXEC ('DROP Table ' + #TableName)
SELECT NAME
FROM sys.tables AS t
WHERE t.name = 'Test201711'
I would guess the problem is the semicolon.
Declare #ste nvarchar(max);
set #ste = '
if exists (select *
from INFORMATION_SCHEMA.TABLES
where TABLE_NAME = ''[tablename]''
)
Drop table [tablename]
';
set #ste = replace(#ste, '[tablename]', CONVERT(varchar(6), getdate(), 112));
print #ste
exec sp_executesql #ste;
Notes:
This constructs the table name once and then uses replace() to put that into the query string.
The semicolon at the end of the if is removed.
Use sp_executesql. It is much more powerful than exec(), even if parameters are not useful in this case.
You can also do this with a try/catch block:
begin try
drop table [tablename]
end try
begin catch
-- assume table doesn't exist and ignore error
end catch;
Related
Output I'm trying to get to;
(Database name = ATT)
Table Name
Column name
MAX loaded date = MAX(loaded_date) for this column only
loaded_date is a column in around 50 tables in a database with the same name and datatype (Datetime)
select * FROM sys.tables
select * FROM syscolumns
I've been exploring the system tables without much luck, looking at some posts it may be done dynamic SQL which I've never done.
You can write an sql that writes an sql..
SELECT REPLACE(
'select ''{tn}'' as table_name, max(loaded_date) as ld from {tn} union all'
,'{tn}',table_name)
FROM
information_schema.columns
WHERE
column_name = 'loaded_date'
Run that, then copy all but the final UNION ALL out of the results window and into the query window, and run again
If you wanted to get all this into a single string for dynamic exec, i guess it'd look like (untested) a procedure that contained:
DECLARE #x NVARCHAR(MAX);
SELECT #x =
STRING_AGG(
REPLACE(
'select ''{tn}'' as table_name, max(loaded_date) as ld from {tn}'
,'{tn}',table_name)
,' union all ')
FROM
information_schema.columns
WHERE
column_name = 'loaded_date';
EXECUTE sp_executesql #x;
If your SQLS is old and doesnt have string_agg it's a bit more awkward - but there are many examples of "turn rows into CSV" in sql server that look like STUFF..FOR XML PATH - https://duckduckgo.com/?t=ffab&q=rows+to+CSV+SQLS&ia=web
I wrote up a more permanent type of script that does this. It returns a result set of the list of tables in the current database with a column named loaded_date along with the MAX(loaded_date) result from each table. This script individually queries each table by looping through and running the query on each table individually and keeping track of the max value for each table in a table variable. It also has a #Debug variable that allows you to see the text of the queries that would be run instead of actually running them and implements custom error message to troubleshoot any issues.
/*disable row count messages*/
SET NOCOUNT ON;
/*set to 1 to debug (aka just print queries instead of running)*/
DECLARE #Debug bit = 0;
/*get list of tables to query and assign a unique index to row to assist in looping*/
DECLARE #TableList TABLE(
SchemaAndTableName nvarchar(257) NOT NULL
,OrderToQuery bigint NOT NULL
,MaxLoadedDate datetime NULL
,PRIMARY KEY (OrderToQuery)
);
INSERT INTO #TableList (SchemaAndTableName,OrderToQuery)
SELECT
CONCAT(QUOTENAME(s.name),N'.', QUOTENAME(t.name)) AS SchemaAndTableName
,ROW_NUMBER() OVER(ORDER BY s.name, t.name) AS OrderToQuery
FROM
sys.columns AS c
INNER JOIN sys.tables AS t ON c.object_id = t.object_id
INNER JOIN sys.schemas AS s ON t.schema_id = s.schema_id
WHERE
c.name = N'loaded_date';
/*declare and set some variables for loop*/
DECLARE #NumTables int = (SELECT TOP (1) OrderToQuery FROM #TableList ORDER BY OrderToQuery DESC);
DECLARE #I int = 1;
DECLARE #CurMaxDate datetime;
DECLARE #CurTable nvarchar(257);
DECLARE #CurQuery nvarchar(max);
/*start loop*/
WHILE #I <= #NumTables
BEGIN
/*build text of current query*/
SET #CurTable = (SELECT SchemaAndTableName FROM #TableList WHERE OrderToQuery = #I);
SET #CurQuery = CONCAT(N'SELECT #MaxDateOut = MAX(loaded_date) FROM ', #CurTable, N';');
/*check debugging status*/
IF #Debug = 0
BEGIN
BEGIN TRY
EXEC sys.sp_executesql #stmt = #CurQuery
,#params = N'#MaxDateOut datetime OUTPUT'
,#MaxDateOut = #CurMaxDate OUTPUT;
END TRY
BEGIN CATCH
DECLARE #ErrorMessage nvarchar(max) = CONCAT(
N'Error querying table ', #CurTable, N'.', NCHAR(13), NCHAR(10)
,N'Errored query: ', NCHAR(13), NCHAR(10), #CurQuery, NCHAR(13), NCHAR(10)
,N'Error message: ', ERROR_MESSAGE()
);
RAISERROR(#ErrorMessage,16,1) WITH NOWAIT;
/*on error end loop so error can be investigated*/
SET #I = #NumTables + 1;
END CATCH;
END;
ELSE /*currently debugging*/
BEGIN
PRINT(CONCAT(N'Debug output: ', #CurQuery));
END;
/*update value in our table variable*/
UPDATE #TableList
SET MaxLoadedDate = #CurMaxDate
WHERE
OrderToQuery = #I;
/*increment loop*/
SET #I = #I + 1;
END;
SELECT
SchemaAndTableName AS TableName
,MaxLoadedDate AS Max_Loaded_date
FROM
#TableList;
I like this solution better as querying each table one at a time would be much less system impact than attempting one large UNION ALL query. Querying a large set of a tables all at once could cause some serious resource semaphore or locking contention (depending on usage of your db).
It is fairly well commented, but let me know if something is not clear.
Also, just a note, dynamic SQL should be used as a last resort. I provided this script to answer your question, but you should explore better options than something like this.
You can go for undocumented stored procedure sp_MSforeachtable. But, don't use in production code, as this stored procedure might not be available in future versions.
Read more on sp_MSforeachtable
EXEC sp_MSforeachtable 'SELECT ''?'' as tablename, max(loaded_Date) FROM ?'
I am wondering if there is any way to do this. We have a program that does data modeling for us (IDA), and it will generate at times hundreds of different alter/delete/update statements for us. The script works, except it does not meet the requirement of being able to be ran multiple times, which we sometimes need due to devops work. I haven't been able to find a way for the modeler to automatically add an IF NOT EXISTS to each statement, and so this means manually needing to add it to each one.
Is there a way to wrap the entire script in one IF NOT EXISTS? or handle this with some other kind of loop or flag I don't know about?
Example:
Currently we would have to do this:
IF NOT EXISTS (
SELECT * FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = 'USERS' AND COLUMN_NAME = 'LASTNAME'
)
BEGIN
ALTER TABLE DBO.USERS ADD LASTNAME CHAR(2) NULL
END;
GO
IF NOT EXISTS (
SELECT * FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = 'ASSETS' AND COLUMN_NAME = 'ASSETTYPE'
)
BEGIN
ALTER TABLE DBO.ASSETS ADD ASSETTYPE CHAR(2) NULL
END;
GO
IF NOT EXISTS (
SELECT * FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = 'ADDRESS' AND COLUMN_NAME = 'LINE3'
)
BEGIN
ALTER TABLE DBO.ADDRESS ADD LINE3 CHAR(2) NULL
END;
GO
Whereas I'd like to be able to not need to add the IF NOT EXISTS to every select, just something to indicate for the script to automatically check if it exists first.
Any thoughts? Thanks.
You could try:
IF COL_LENGTH('table_name','column_name') IS NULL
BEGIN
/* ALTER TABLE .... */
END
This was obtained from this forum: How to check if a column exists in a SQL Server table? (Got 958 up votes) or
Add a column to a table, if it does not already exist
You would need to load all the TableName and ColumnName combination into the #TEMP1
through which you need to loop it. Also you can change the data type of the column to a variable as well. Let me know if you need help adapting the code to your needs. You can scale that code to add DB_NAME and different datatypes. But you would need different versions of the code for update and delete
SELECT TABLENAME, COLNAME
INTO #TEMP1
FROM MYTABLE
DECLARE #TABLE_NAME VARCHAR(100)
DECLARE #COL_NAME VARCHAR(100)
DECLARE #SQL VARCHAR(MAX)
WHILE EXISTS (SELECT * FROM #TEMP1)
BEGIN
SELECT TOP 1 #TABLE_NAME = TABLENAME,
#COL_NAME = COLNAME
FROM #TEMP1
SET #SQL = '
IF NOT EXISTS (
SELECT * FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = '+#TABLE_NAME+' AND COLUMN_NAME = '+#COL_NAME+'
)
BEGIN
ALTER TABLE DBO.'+#TABLE_NAME+' ADD '+#COL_NAME+' CHAR(2) NULL
END'
EXEC #SQL
DELETE FROM #TEMP1
WHERE TABLENAME = #TABLE_NAME AND COLNAME = #COL_NAME
END
Suppose I have the following structure to a set of tables in my SQL Server (2012) DB:
StartDate: Col1: Col2: .... Coln:
And, the way the DBA set up the database (have no control over that - I only have query access), all the tables with this structure that I'd want to query have, say, names beginning with MyTbl....
So, I would like to create a query that queries ALL these tables at once to get data for a specific StartDate and I've done it using the following SQL:
declare #t table(tablename varchar(50))
declare #sql varchar(max)
set #sql = ''
insert into #t
SELECT t.name AS table_name FROM sys.tables AS t
WHERE t.name LIKE 'MyTbl%'
select #sql = #sql + 'Select ''' + tablename + ''' as Table_Name, t.* From ' + tablename +
' t where StartDate = ''2015-01-01'' +
' union ' from #t
Select #sql = substring(#sql, 1, len(#sql) - 6)
exec(#sql)
In other words:
Find all tables in my DB with names beginning with MyTbl
Query each table for any data with StartDate = '2015-01-01`
Union all those queries together to get one big dataset result
The SQL works perfectly, but I'm getting quite stuck in creating a stored procedure from this query that can take in a parameter for StartDate and I don't know enough about stored procedures to do this correctly.
How could I convert this into a stored procedure that takes a date in for StartDate (to replace the ''2015-01-01'' in the query)?
Any help / guidance would be GREATLY appreciated!!!
THANKS!!!
I noticed you were not looping through each table .. here is something I had put together
CREATE PROCEDURE get_tabledata (#date DATE)
AS
BEGIN
DECLARE #t TABLE (
id INT IDENTITY(1, 1)
,tablename VARCHAR(50)
)
DECLARE #id INT
DECLARE #tablename VARCHAR(max)
DECLARE #sql VARCHAR(max)
SET #sql = ''
INSERT INTO #t
SELECT t.NAME AS table_name
FROM sys.tables AS t
WHERE t.NAME LIKE 'MyTbl%'
SET #id = ##ROWCOUNT
IF (#id > 0)
BEGIN
WHILE (#id > 0)
BEGIN
SET #tablename = (
SELECT tablename
FROM #t
WHERE id = #id
)
SELECT #sql = #sql + 'Select ' + #tablename + ''' as Table_Name, t.* From ' + #tablename + ' t where StartDate = ' + '' + convert(VARCHAR, #date) + ''
SET #sql = #sql + ' union'
Set #id = #id -1;
END
SELECT #sql = substring(#sql, 1, len(#sql) - 6)
END
EXEC (#sql)
END
While it can be a little dense if you're not used to the styling Microsoft uses on these pages, the best place to start would be the Create Procedure documentation on MSDN
https://msdn.microsoft.com/en-us/library/ms187926.aspx
That said, creating a stored procedure is pretty straight forward. Here's a really simple procedure that takes a #startDate parameter and then just returns it back. This is just to illustrate how and where you define your parameters
create procedure dbo.MyProcedure
-- put your input parameters here
#StartDate date
as
--put the body of your procedure (i.e. everything you've written in your OP) here
select #StartDate
go
YOu'll notice however that if you run this twice in a row, you get an error, because it tries to build the same procedure again. Another thing which can come in handy is adding some code before your procedure which will basically check to see if it already exists, and if it does, alter the procedure rather than just blindly re-create it.
This is a snippet from a template I use quite often which handles all of that logic for you. The simplest way to use this is press CTRL-SHIFT-M, which brings up a dialogue to replace all those tags with values you provide.
use [<Database Name, sysname,>]
go
if not exists (select 1
from sys.procedures with(nolock)
where name = '<Procedure Name, sysname,>'
and [schema_id] = schema_id('<Schema, sysname,dbo>')
and type = 'P'
)
exec ('create procedure [<Schema, sysname,dbo>].[<Procedure Name, sysname,>]
as
select ''Procedure not defined.'' as ErrorDescription
return')
--Executed as dynamic SQL since SQL Server Management Studio considures the straight SQL code a syntax error for some reason on the create procedure statement
GO
alter procedure [<Schema, sysname,dbo>].[<Procedure Name, sysname,>]
<Parm 1 Name, sysname,include [#]> <Parm 1 Datatype, sysname,><Parm 1 Default, sql_variant,include [=] if used>,
<Parm 2 Name, sysname,include [#]> <Parm 2 Datatype, sysname,><Parm 2 Default, sql_variant,include [=] if used>
as
/*******************************************************************************************************
********************************************************************************************************/
---------------------------------------------
-- declare variables
---------------------------------------------
---------------------------------------------
-- create temp tables
---------------------------------------------
---------------------------------------------
-- set session variables
---------------------------------------------
set nocount on
---------------------------------------------
-- body of stored procedure
---------------------------------------------
return
I'm currently shifting roles at my job and trying to teach myself some SQL Skills.
Scenario: I'm in charge of 1 database - 10 tables with 10 Primary Keys. Every month, our code team publishes updates to the tables. I am suppose to drop the tables and generate scripts to create the updated tables.
Rather than just drop the old tables and stored procedures, I want to rename my current tables to preserve the structure/data for whatever reason.
In my database, I have an additional table called "TableUpdateList" with 1 column "TableName" and 10 rows - each row containing the name of the updated column (Row 1 = TableName1, Row 2 = TableName2, Row 3 = TableName3)
I would like to be able to "loop" through the TableUpdateList Table and insert each value into a set of SQL statements.
For Example, here are the SQL statements I want to run:
--drop the previous backup table
IF EXISTS (SELECT * FROM INFORMATION_SCHEMA.TABLES where TABLE_NAME = '*TableName1*'+'_Old') DROP TABLE TableName1_Old
-- rename the current tables to _old
EXEC sp_rename *TableName1*, TableName1_Old;
I'm trying to find a way to scroll through the column of my TableUpdateList and run the above two statements filling in where I've italicized with whatever value is present in that row.
Just taking a wild stab because I think in order to get an answer here, you have to try something so here is my pseudo-code:
Declare #TableNames as List
For i in #TableNames
IF EXISTS (SELECT * FROM INFORMATION_SCHEMA.TABLES where TABLE_NAME = '*i*'+'_Old') DROP TABLE TableName1_Old
-- rename the current tables to _old
EXEC sp_rename *i*, TableName1_Old;
Oi, thanks in advance for any help or a point in the right direction to where I could do some further reading about the above online.
You can use sp_executesql with CURSORS for such type of work. Here is what i think you need:
Test objects:
CREATE TABLE TableName1 ( ID INT )
GO
CREATE TABLE TableName2 ( ID INT )
GO
CREATE TABLE TableNames ( Name NVARCHAR(MAX) )
GO
INSERT INTO TableNames
VALUES ( 'TableName1' ),
( 'TableName2' )
Script itself:
DECLARE #name NVARCHAR(MAX) ,
#dropStatement NVARCHAR(MAX),
#renameStatement NVARCHAR(MAX)
DECLARE cur CURSOR FAST_FORWARD READ_ONLY
FOR
SELECT Name
FROM dbo.TableNames
OPEN cur
FETCH NEXT FROM cur INTO #name
WHILE ##FETCH_STATUS = 0
BEGIN
IF EXISTS ( SELECT *
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME = #name + '_Old' )
BEGIN
SET #dropStatement = 'DROP TABLE ' + #name + '_Old'
EXEC sp_executesql #dropStatement
END
SET #renameStatement = 'sp_rename ' + #name + ', ' + #name + '_Old';
EXEC sp_executesql #renameStatement
FETCH NEXT FROM cur INTO #name
END
CLOSE cur
DEALLOCATE cur
After this you should add TableName1 and TableName2 again.
Cursors must be avoided as long as possible.
--Preparing script which would check if the old tables exists. If it does,
--it drops the old table
--e.g. first the value 'Table1' is found in TableUpdateList table.
--Then, Table1_Old is deleted and Table1 is renamed to Table1_Old
SELECT 'DROP TABLE ' + b.name + '_Old; EXEC sp_rename ''' + b.name+ ''', ''' + b.name+ '_Old;''' AS [Action]
INTO #Action
FROM INFORMATION_SCHEMA.TABLES A JOIN TableUpdateList B ON A.TABLE_NAME = b.NAME + '_Old'
DECLARE #sql VARCHAR(8000)
SELECT #sql = COALESCE(#sql + ' ', '') + [Action]
FROM #Action
select #sql
--EXEC (#sql)
First verify the value of variable #sql. Then, uncomment the last line to execute the code.
SQL fiddle
In a stored procedure I pass a table name as the input variable.
I want to return the number of rows of this table with that stored procedure.
I tried something like this but it did not work:
declare #maxRowCount bigint
exec('set '+ #maxRowCount + ' =(select COUNT(1) from ' + #tableName + ')')
This is SQL Server 2008.
You can try this
CREATE PROCEDURE dbo.sp_selectcount
#tablename NVARCHAR(200)
AS
DECLARE #cmd NVARCHAR (255)
SET #cmd = 'SELECT count(*) from ' + #tablename
EXEC sp_executesql #cmd
The following example should give you something to work with.
-- fully qualify your table name (this is probably an input value in your sproc?)
-- please note that I use system view master.sys.tables as an example table here
DECLARE #tablename NVARCHAR(MAX) = N'[master].[sys].[tables]';
-- build the sql statement that you will execute
DECLARE #sql NVARCHAR(MAX) = N'SELECT COUNT(*) FROM ' + #tablename;
-- create a variable to hold the number of rows later on
DECLARE #nrofrows BIGINT;
-- create a temp table to store the result of executing the sql statement
CREATE TABLE #temp (NrOfRows BIGINT);
-- insert the result of the execution of the sql statement into the temp table
INSERT INTO #temp
EXECUTE(#sql);
-- extract the number of rows from the temp table
SET #nrofrows = (SELECT NrOfRows FROM #temp);
-- check the result so you can test!
PRINT #nrofrows;
If you want good background information on dynamic SQL, check out Erland Sommarskogs article The Curse and Blessings of Dynamic SQL.
You should remove the quotes around #maxRowCount.
Try this:
declare #maxRowCount bigint
exec('set #maxRowCount =(select COUNT(*) from ' + #tableName + ')')
OR
exec('SELECT #maxRowCount = COUNT(*) from ' + #tableName)
Analysis:
With the query you tried, it will execute:
set blablabla = (select count(1) from MyTable)
By removing the quotes:
set #maxRowCount = (select count(*) from MyTable)
You can try this instead.
declare #maxRowCount bigint(5)
exec('SELECT COUNT(*) INTO #maxRowCount FROM ' + #tableName)