How to delete all rows from all tables in a SQL Server database?
179
votes
11 Answers
293
votes
Note that TRUNCATE won't work if you have any referential integrity set.
In that case, this will work:
EXEC sp_MSForEachTable 'DISABLE TRIGGER ALL ON ?'
GO
EXEC sp_MSForEachTable 'ALTER TABLE ? NOCHECK CONSTRAINT ALL'
GO
EXEC sp_MSForEachTable 'DELETE FROM ?'
GO
EXEC sp_MSForEachTable 'ALTER TABLE ? WITH CHECK CHECK CONSTRAINT ALL'
GO
EXEC sp_MSForEachTable 'ENABLE TRIGGER ALL ON ?'
GO
Edit: To be clear, the ? in the statements is a ?. It's replaced with the table name by the sp_MSForEachTable procedure.
22
votes
In my recent project my task was to clean an entire database by using sql statement and each table having many constraints like Primary Key and Foreign Key. There are more than 1000 tables in database so its not possible to write a delete query on each and ever table.
By using a stored procedure named sp_MSForEachTable which allows us to easily process some code against each and every table in a single database. It means that it is used to process a single T-SQL command or a different T-SQL commands against every table in the database.
So follow the below steps to truncate all tables in a SQL Server Database:
Step 1- Disable all constraints on the database by using below sql query :
EXEC sys.sp_msforeachtable 'ALTER TABLE ? NOCHECK CONSTRAINT ALL'
Step 2- Execute a Delete or truncate operation on each table of the database by using below sql command :
EXEC sys.sp_msforeachtable 'DELETE FROM ?'
Step 3- Enable all constraints on the database by using below sql statement:
EXEC sys.sp_MSForEachTable 'ALTER TABLE ? CHECK CONSTRAINT ALL'
16
votes
I had to delete all the rows and did it with the next script:
DECLARE @Nombre NVARCHAR(MAX);
DECLARE curso CURSOR FAST_FORWARD
FOR
Select Object_name(object_id) AS Nombre from sys.objects where type = 'U'
OPEN curso
FETCH NEXT FROM curso INTO @Nombre
WHILE (@@FETCH_STATUS <> -1)
BEGIN
IF (@@FETCH_STATUS <> -2)
BEGIN
DECLARE @statement NVARCHAR(200);
SET @statement = 'DELETE FROM ' + @Nombre;
print @statement
execute sp_executesql @statement;
END
FETCH NEXT FROM curso INTO @Nombre
END
CLOSE curso
DEALLOCATE curso
Hope this helps!
14
votes
In my case, I needed to set QUOTED_IDENTIFIER on. This led to a slight modification of Mark Rendle's answer above:
EXEC sp_MSforeachtable 'DISABLE TRIGGER ALL ON ?'
GO
EXEC sp_MSforeachtable 'ALTER TABLE ? NOCHECK CONSTRAINT ALL'
GO
EXEC sp_MSforeachtable 'SET QUOTED_IDENTIFIER ON; DELETE FROM ?'
GO
EXEC sp_MSforeachtable 'ALTER TABLE ? CHECK CONSTRAINT ALL'
GO
EXEC sp_MSforeachtable 'ENABLE TRIGGER ALL ON ?'
GO
13
votes
Here is a solution that:
- Drops constraints (thanks to this post)
- Iterates through
INFORMATION_SCHEMA.TABLESfor a particular database SELECTStables based on some search criteria- Deletes all the data from those tables
- Re-adds constraints
- Allows for ignoring of certain tables such as
sysdiagramsand__RefactorLog
I initially tried EXECUTE sp_MSforeachtable 'TRUNCATE TABLE ?', but that deleted my diagrams.
USE <DB name>;
GO
-- Disable all constraints in the database
EXEC sp_MSforeachtable "ALTER TABLE ? NOCHECK CONSTRAINT all"
declare @catalog nvarchar(250);
declare @schema nvarchar(250);
declare @tbl nvarchar(250);
DECLARE i CURSOR LOCAL FAST_FORWARD FOR select
TABLE_CATALOG,
TABLE_SCHEMA,
TABLE_NAME
from INFORMATION_SCHEMA.TABLES
where
TABLE_TYPE = 'BASE TABLE'
AND TABLE_NAME != 'sysdiagrams'
AND TABLE_NAME != '__RefactorLog'
OPEN i;
FETCH NEXT FROM i INTO @catalog, @schema, @tbl;
WHILE @@FETCH_STATUS = 0
BEGIN
DECLARE @sql NVARCHAR(MAX) = N'DELETE FROM [' + @catalog + '].[' + @schema + '].[' + @tbl + '];'
/* Make sure these are the commands you want to execute before executing */
PRINT 'Executing statement: ' + @sql
-- EXECUTE sp_executesql @sql
FETCH NEXT FROM i INTO @catalog, @schema, @tbl;
END
CLOSE i;
DEALLOCATE i;
-- Re-enable all constraints again
EXEC sp_MSforeachtable "ALTER TABLE ? WITH CHECK CHECK CONSTRAINT all"
4
votes
Set nocount on
Exec sp_MSforeachtable 'Alter Table ? NoCheck Constraint All'
Exec sp_MSforeachtable
'
If ObjectProperty(Object_ID(''?''), ''TableHasForeignRef'')=1
Begin
-- Just to know what all table used delete syntax.
Print ''Delete from '' + ''?''
Delete From ?
End
Else
Begin
-- Just to know what all table used Truncate syntax.
Print ''Truncate Table '' + ''?''
Truncate Table ?
End
'
Exec sp_MSforeachtable 'Alter Table ? Check Constraint All'
1
votes
0
votes
For some requirements we might have to skip certain tables. I wrote the below script to add some extra conditions to filter the list of tables. The below script will also display the pre delete count and post delete count.
IF OBJECT_ID('TEMPDB..#TEMPRECORDCOUNT') IS NOT NULL
DROP TABLE #TEMPRECORDCOUNT
CREATE TABLE #TEMPRECORDCOUNT
( TABLENAME NVARCHAR(128)
,PREDELETECOUNT BIGINT
,POSTDELETECOUNT BIGINT
)
INSERT INTO #TEMPRECORDCOUNT (TABLENAME, PREDELETECOUNT, POSTDELETECOUNT)
SELECT O.name TableName
,DDPS.ROW_COUNT PREDELETECOUNT
,NULL FROM sys.objects O
INNER JOIN (
SELECT OBJECT_ID, SUM(row_count) ROW_COUNT
FROM SYS.DM_DB_PARTITION_STATS
GROUP BY OBJECT_ID
) DDPS ON DDPS.OBJECT_ID = O.OBJECT_ID
WHERE O.type = 'U' AND O.name NOT LIKE 'OC%' AND O.schema_id = 1
DECLARE @TableName NVARCHAR(MAX);
DECLARE TableDeleteCursor CURSOR FAST_FORWARD
FOR
SELECT TableName from #TEMPRECORDCOUNT
OPEN TableDeleteCursor
FETCH NEXT FROM TableDeleteCursor INTO @TableName
WHILE (@@FETCH_STATUS <> -1)
BEGIN
IF (@@FETCH_STATUS <> -2)
BEGIN
DECLARE @STATEMENT NVARCHAR(MAX);
SET @STATEMENT = ' DISABLE TRIGGER ALL ON ' + @TableName +
'; ALTER TABLE ' + @TableName + ' NOCHECK CONSTRAINT ALL' +
'; DELETE FROM ' + @TableName +
'; ALTER TABLE ' + @TableName + ' CHECK CONSTRAINT ALL' +
'; ENABLE TRIGGER ALL ON ' + @TableName;
PRINT @STATEMENT
EXECUTE SP_EXECUTESQL @STATEMENT;
END
FETCH NEXT FROM TableDeleteCursor INTO @TableName
END
CLOSE TableDeleteCursor
DEALLOCATE TableDeleteCursor
UPDATE T
SET T.POSTDELETECOUNT = I.ROW_COUNT
FROM #TEMPRECORDCOUNT T
INNER JOIN (
SELECT O.name TableName, DDPS.ROW_COUNT ROW_COUNT
FROM sys.objects O
INNER JOIN (
SELECT OBJECT_ID, SUM(row_count) ROW_COUNT
FROM SYS.DM_DB_PARTITION_STATS
GROUP BY OBJECT_ID
) DDPS ON DDPS.OBJECT_ID = O.OBJECT_ID
WHERE O.type = 'U' AND O.name NOT LIKE 'OC%' AND O.schema_id = 1
) I ON I.TableName COLLATE DATABASE_DEFAULT = T.TABLENAME
SELECT * FROM #TEMPRECORDCOUNT
ORDER BY TABLENAME ASC
0
votes
This answer builds on Zach Smith's answer by resetting the identity column as well:
- Disabling all constraints
- Iterating through all tables except those you choose to exclude
- Deletes all rows from the table
- Resets the identity column if one exists
- Re-enables all constraints
Here is the query:
-- Disable all constraints in the database
EXEC sp_msforeachtable "ALTER TABLE ? NOCHECK CONSTRAINT all"
declare @catalog nvarchar(250);
declare @schema nvarchar(250);
declare @tbl nvarchar(250);
DECLARE i CURSOR LOCAL FAST_FORWARD FOR select
TABLE_CATALOG,
TABLE_SCHEMA,
TABLE_NAME
from INFORMATION_SCHEMA.TABLES
where
TABLE_TYPE = 'BASE TABLE'
AND TABLE_NAME != 'sysdiagrams'
AND TABLE_NAME != '__RefactorLog'
-- Optional
-- AND (TABLE_SCHEMA = 'dbo')
OPEN i;
FETCH NEXT FROM i INTO @catalog, @schema, @tbl;
WHILE @@FETCH_STATUS = 0
BEGIN
DECLARE @sql NVARCHAR(MAX) = N'DELETE FROM [' + @catalog + '].[' + @schema + '].[' + @tbl + '];'
/* Make sure these are the commands you want to execute before executing */
PRINT 'Executing statement: ' + @sql
--EXECUTE sp_executesql @sql
-- Reset identity counter if one exists
IF ((SELECT OBJECTPROPERTY( OBJECT_ID(@catalog + '.' + @schema + '.' + @tbl), 'TableHasIdentity')) = 1)
BEGIN
SET @sql = N'DBCC CHECKIDENT ([' + @catalog + '.' + @schema + '.' + @tbl + '], RESEED, 0)'
PRINT 'Executing statement: ' + @sql
--EXECUTE sp_executesql @sql
END
FETCH NEXT FROM i INTO @catalog, @schema, @tbl;
END
CLOSE i;
DEALLOCATE i;
-- Re-enable all constraints again
EXEC sp_msforeachtable "ALTER TABLE ? WITH CHECK CHECK CONSTRAINT all"
0
votes
--Load tables to delete from
SELECT
DISTINCT
' Delete top 1000000 from <DBName>.<schema>.' + c.TABLE_NAME + ' WHERE <Filter Clause Here>' AS query,c.TABLE_NAME AS TableName, IsDeleted=0, '<InsertSomeDescriptorHere>' AS [Source]--,t.TABLE_TYPE, c.*
INTO dbo.AllTablesToDeleteFrom
FROM INFORMATION_SCHEMA.TABLES AS t
INNER JOIN information_schema.columns c ON c.TABLE_NAME = t.TABLE_NAME
WHERE c.COLUMN_NAME = '<column name>'
AND c.TABLE_SCHEMA = 'dbo'
AND c.TABLE_CATALOG = '<DB Name here>'
AND t.TABLE_TYPE='Base table'
--AND t.TABLE_NAME LIKE '<put filter here>'
DECLARE @TableSelect NVARCHAR(1000)= '';
DECLARE @Table NVARCHAR(1000)= '';
DECLARE @IsDeleted INT= 0;
DECLARE @NumRows INT = 1000000;
DECLARE @Source NVARCHAR(50)='';
WHILE ( @IsDeleted = 0 )
BEGIN
--This grabs one table at a time to be deleted from. @TableSelect has the sql to execute. it is important to order by IsDeleted ASC
--because it will pull tables to delete from by those that have a 0=IsDeleted first. Once the loop grabs a table with IsDeleted=1 then this will pop out of loop
SELECT TOP 1
@TableSelect = query,
@IsDeleted = IsDeleted,
@Table = TableName,
@Source=[a].[Source]
FROM dbo.AllTablesToDeleteFrom a
WHERE a.[Source]='SomeDescriptorHere'--use only if needed
ORDER BY a.IsDeleted ASC;--this is required because only those records returned with IsDeleted=0 will run through loop
--SELECT @Table; can add this in to monitor what table is being deleted from
WHILE ( @NumRows = 1000000 )--only delete a million rows at a time?
BEGIN
EXEC sp_executesql @TableSelect;
SET @NumRows = @@ROWCOUNT;
--IF @NumRows = 1000000 --can do something here if needed
--One wants this loop to continue as long as a million rows is deleted. Once < 1 million rows is deleted it pops out of loop
--and grabs next table to delete
-- BEGIN
--SELECT @NumRows;--can add this in to see current number of deleted records for table
INSERT INTO dbo.DeleteFromAllTables
( tableName,
query,
cnt,
[Source]
)
SELECT @Table,
@TableSelect,
@NumRows,
@Source;
-- END;
END;
SET @NumRows = 1000000;
UPDATE a
SET a.IsDeleted = 1
FROM dbo.AllTablesToDeleteFrom a
WHERE a.TableName = @Table;
--flag this as deleted so you can move on to the next table to delete from
END;
