Delete large table in Batch and Update source table



 /***************************************
  if object_id('Table1','U') is not null
  drop table Table1 ;

  create table Table1 ( id int, filename varchar(50));

  if object_id('Table2','U') is not null
  drop table Table2 ;
create table Table2 ( id int, filename varchar(50), FILE_DESC  varchar(50) , [Processed_date] datetime)

--drop table table1, table2
truncate table table1
truncate table table2

insert into Table1 values (1,'a1'),(2,'a2'), (3,'a3'),(4,'a4'), (5,'a5'),(6,'a6'), (7,'a7'),(8,'a8'), (9,'a9'),(10,'a10'),
(11,'a11'),(12,'a12'), (13,'a13'),(14,'a14'), (15,'a5'),(16,'a16'), (17,'a17'),(18,'a18'), (19,'a19'),(20,'a20')

insert into Table2 values (1,'a1', 'EDI', '1/1/2000' ),(2,'a2', 'EDI', '1/1/2000'), (3,'a3', 'EDI', '1/1/2000'),(4,'a4', 'EDI', '1/1/2000'), (5,'a5', 'EDI', '1/1/2000')
,(6,'a6', 'EDI', '1/1/2000'), (7,'a7', 'EDI', '1/1/2000'),(8,'a8', 'EDI', '1/1/2000'), (9,'a9', 'EDI', '1/1/2000'),(10,'a10', 'EDI', '1/1/2000'),
(11,'a11', 'EDI', '1/1/2000'),(12,'a12', 'EDI', '1/1/2000'), (13,'a13', 'EDI', '1/1/2000'),(14,'a14', 'EDI', '1/1/2000'), (15,'a5', 'EDI', '1/1/2000')
,(16,'a16', 'EDI', '1/1/2000'), (17,'a17', 'EDI', '1/1/2000'),(18,'a18', 'EDI', '1/1/2000'), (19,'a19', 'EDI', '1/1/2000'),(20,'a20', 'EDI', '1/1/2000')


select * from table1
select * from table2


 ***************************************/


declare @Chunk int=5,  @ToBeDeleted int = 1
  --if object_id('#MyTableVar','U') is not null
  --drop table #MyTableVar ;

--Create table #MyTableVar (filename VARCHAR(32))
  
WHILE @ToBeDeleted > 0
  BEGIN
      BEGIN TRAN

declare @myTableVar table (filename varchar(30)) ;


	  ;with mycte as (
	  select row_number() Over(Order by b.[Processed_date]) rn ,a.filename
	  FROM Table1 a
INNER JOIN Table2 b ON a.filename = b.filename
WHERE  b.FILE_DESC = 'EDI'
AND b.[Processed_date] < DATEADD (WEEK, -10, Getdate ()) )
 
      

	 
	  DELETE  Table1
	  OUTPUT DELETED.filename into @myTableVar
	  From Table1 a
	  inner join mycte m On a.filename = m.filename

	  Where  rn< @Chunk ;

	  	       
		   SET @ToBeDeleted = @@ROWCOUNT
	   
 
	--Update the source table
	  Update t2 
	  Set [Processed_date] =getdate()
	  From Table2 t2 INNER JOIN @myTableVar m on  m.filename=t2.filename

delete from @myTableVar;

 
 
 
 
      PRINT 'Deleted/Updated rows: ' + Cast(@ToBeDeleted AS VARCHAR(10))
 
      COMMIT TRAN


  END





 
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