I have a SQL database and I would like to remove almost all tables related to a specific schema except a couple of them. Therefore I think I would need to edit the following sql query (which removes all tables of a specific schema):
EXEC sp_MSforeachtable
#command1 = 'DROP TABLE ?'
, #whereand = 'AND SCHEMA_NAME(schema_id) = ''your_schema_name'' '
Would you be able to suggest a smart and elegant way so that I can add a list of tables that I would like to keep and remove everything else?
If you want to keep using sp_msforeachtable, pass in the set of tables names to keep using a temp table. Here's an example using the boo schema:
create schema boo;
create table boo.t(i int);
create table #keep (name sysname);
insert #keep values ('myFirsttable'), ('mySecondTable'), ('myThirdTable');
exec sp_msforeachtable
#command1='drop table ?; print ''dropped ?''',
#whereand = 'and schema_name(schema_id) = ''your_schema_name'' and object_name(object_id) not in (select name from #keep)';
But personally, I'd probably just write my own stored procedure with a cursor. It's harder to mess up.
Note that this solution expects you to put the tables you want to keep into the temp table. Charlieface's solution expects you to put the names of tables you want to drop into the table variable.
You could place a list of tables you want to delete stored in a table variable or Table-Valued Parameter #tables then you can simply execute dynamic SQL with it.
DECLARE #tables TABLE (tablename sysname);
INSERT #tables (tablename)
SELECT t.name
FROM sys.tables t
WHERE t.schema_id = SCHEMA_ID('your_schema_name');
DECLARE #sql nvarchar(max) =
(
SELECT STRING_AGG(CAST(
'DROP TABLE ' + QUOTENAME('your_schema_name') + '.' + QUOTENAME(tablename) + ';'
AS nvarchar(max)), '
' )
FROM #tables
);
EXEC sp_executesql #sql;
Alternatively, select it directly from sys.tables
DECLARE #sql nvarchar(max) =
(
SELECT STRING_AGG(CAST(
'DROP TABLE ' + QUOTENAME(SCHEMA_NAME(t.schema_id)) + '.' + QUOTENAME(t.name) + ';'
AS nvarchar(max)), '
' )
FROM sys.tables t
WHERE t.schema_id = SCHEMA_ID('your_schema_name')
);
EXEC sp_executesql #sql;
Related
I need to create a dynamic sql query in order to return all values in the first column of a table. The table's name needs to be a variable #tableName ( i will run this query for multiple tables depending on several conditions). Also, i don't know exactly the first column's name but it is formed out of Id_#tableName .
I need something like below but written dinamically:
select
(select column_name from INFORMATION_SCHEMA.columns where table_Name= #tableName and ordinal_position=1)
from #tableName
Could you please help me? Thank you in advance!
USE AdventureWorks;
GO
DECLARE #ObjectName SYSNAME = 'Sales.SalesOrderHeader';
DECLARE #SQL NVARCHAR(MAX);
SELECT
#SQL = 'SELECT ' + QUOTENAME(name) + ' FROM ' + #ObjectName
FROM
sys.columns
WHERE
object_id = OBJECT_ID(#ObjectName)
AND column_id = 1;
EXEC sp_executesql #SQL;
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
I'm debugging a stored procedure by running various pieces of the code manually. The problem is the code creates a lot of temp tables, so I have to add a lot of "DROP TABLE #name" to the start of my query in order for it to work for multiple runs.
Is there a way to drop all temp tables before my query runs?
You can find the solution in an old post here ...
I would suggest first make sure that its only deleting the table you want to delete, by print the query prepared
declare #sql nvarchar(max)
select #sql = isnull(#sql+';', '') + 'drop table ' + quotename(name)
from tempdb..sysobjects
where name like '##%'
select #sql
And then if all table names look good to you. Run with exec(SQL)
EXEC( #sql )
Below is the test I did for this, and it worked for because my temp tables has names starting with '##' which in my cases didn't pulled any global temp tables.
declare #sqlCreate nvarchar(max)
declare #sqldrop nvarchar(max)
--Creating Temp tables
set #sqlCreate = 'create table ##tempTable1( c int, b int, a nvarchar(50) ) ; create table ##tempTable2( c int, b int, a nvarchar(50) )'
EXEC( #sqlCreate )
--Preparing drop statement
select #sqldrop = isnull(#sqldrop+';', '') + 'drop table ' + quotename(name)
from tempdb..sysobjects
where name like '##%'
--Making sure that only my temp tables are returned.
select #sqldrop
--Executing the drop query
EXEC(#sqldrop)
We have an application that stores logged data in a Database called "ACManager" and Table called "Events_1".
When this table gets to a certain number of records the software creates another table called "Events_2". This continues as the data grows. I need to be able to query this data automatically as if it's all in one table without interference. Using a UNION will eventually create invalid querys when a new table is created dynamically by the application. Please also take into account performance.
So we need to Query as one table without UNION:
Select *
FROM ACManager.Events_1 , ACManager.Events_2 , ACManager.Events_xxxx(as needed)
Use dynamic sql. try this
DECLARE #query VARCHAR(MAX)
SET #query='Select *
FROM SELECT STUFF((SELECT '','' + name
from sys.tables where name like ''Events%''
FOR XML PATH('''')), 1, 1, '''') '
EXEC #query
In this script you create procedure. In body of the procedure uses dynamic sql which build sql statement and then run this statement
CREATE PROCEDURE dbo.getEvents
AS
DECLARE #dml nvarchar(max)
SELECT #dml = COALESCE(#dml + ' UNION ALL SELECT * FROM ', 'SELECT * FROM ')
+ QUOTENAME(s.name) + '.' + QUOTENAME(t.name)
FROM sys.schemas s INNER JOIN sys.tables t ON s.schema_id = t.schema_id
WHERE s.name = 'dbo' AND t.name LIKE 'event%'
--PRINT #dml
EXEC sp_executesql #dml
See demo on SQLFiddle
It is no problem to list all tables with schemas on a server
SELECT SCHEMA_NAME(schema_id), name FROM sys.tables
How can I determine which database the tables reside in ?
sys.tables exists in all databases so I am not following the fact that you don't know the db you are in. you can run DB_NAME(DB_ID()) to get the db name
SELECT DB_NAME(DB_ID()),SCHEMA_NAME(schema_id), name FROM sys.tables
but in this case DB_NAME(DB_ID()) will return the same value for every row
to do it for all database, you can do this
EXEC sp_msforeachdb 'use [?] SELECT ''?'',SCHEMA_NAME(schema_id), name
FROM sys.tables'
You can of course dump it into a table as well
CREATE TABLE #output (DatabaseName VARCHAR(1000),
SchemaName VARCHAR(1000),
TableName VARCHAR(1000))
INSERT #output
EXEC sp_msforeachdb 'use [?] SELECT ''?'',SCHEMA_NAME(schema_id), name
FROM sys.tables'
SELECT * FROM #output
Just as a FYI, the sp_msforeachdb proc is undocumented and you should not use it for production code, to quickly find something is fine, for production code roll your own version of this proc
See also Aaron Bertrand's posts here:
Making a more reliable and flexible sp_MSforeachdb
Execute a Command in the Context of Each Database in SQL Server
I ran into this problem when I was creating query that I wanted to be able to run against a different database on my server, and include the other database's name name without hard-coding it into the query.
The query essentially looked like this:
SELECT DB_NAME() db_name
, SCHEMA_NAME(schema_id) schema_name
, name table_name
FROM OtherDB.sys.tables --The OtherDB is to specify that I am running
--this for a different database than the one
--I'm logged in to for my current session.
The problem was that even though I specify OtherDB.sys.tables in the from clause, DB_NAME() always returned the current database I was in. Yes, I could put a USE OtherDB at the beginning, but it seemed like there should be another way. I looked through every sys view I could find, but could never find anything that would link sys.databases and sys.tables.
What I eventually found was SQL Server's INFORMATION_SCHEMA.TABLES This view includes the Database name as the first column (referred to as TABLE_CATAOLG).
SELECT TABLE_CATALOG
, TABLE_SCHEMA
, TABLE_NAME
, TABLE_TYPE
FROM INFORMATION_SCHEMA.TABLES
With these views, you can easily compare the tables in two databases:
SELECT a.TABLE_CATALOG
, a.TABLE_SCHEMA
, a.TABLE_NAME
, a.TABLE_TYPE
, b.TABLE_CATALOG
, b.TABLE_SCHEMA
, b.TABLE_NAME
, b.TABLE_TYPE
FROM OneDatabase.INFORMATION_SCHEMA.TABLES a
FULL OUTER JOIN TwoDatabase.INFORMATION_SCHEMA.TABLES b
ON a.TABLE_SCHEMA = b.TABLE_SCHEMA
AND a.TABLE_NAME = b.TABLE_NAME
If the databases are on separate servers that are linked you should be able to use this query by using all four parts of the Fully Qualified Table Name.
If your intention is just to include the current database name, why not just:
SELECT DB_NAME(), SCHEMA_NAME(schema_id), name FROM sys.tables;
If your intention is to pull all names from all databases, I personally prefer dynamic SQL like this instead of sp_msforeachdb:
DECLARE #sql NVARCHAR(MAX) = N'';
SELECT #sql += CHAR(13) + CHAR(10) + 'UNION ALL
SELECT ''' + name + ''', s.name, t.name
FROM ' + QUOTENAME(name) + '.sys.tables AS t
INNER JOIN ' + QUOTENAME(name) + '.sys.schemas AS s
ON t.schema_id = s.schema_id'
FROM sys.databases
WHERE database_id > 4;
SET #sql = STUFF(#sql, 1, 13, '');
PRINT #sql;
-- EXEC sp_executesql #sql;