Delete large amount of data in sql server

Question

Suppose that I have a table with 10000000 record. What is difference between this two solution?

1. delete data like :

   DELETE FROM MyTable
            
   
   
           

Answer 1

Found this post on Microsoft TechNet.

Basically, it recommends:

1. By using SELECT INTO, copy the data that you want to KEEP to an intermediate table;
2. Truncate the source table;
3. Copy back with INSERT INTO from intermediate table, the data to the source table;

..

BEGIN TRANSACTION

SELECT  *
   INTO    dbo.bigtable_intermediate
   FROM    dbo.bigtable
   WHERE   Id % 2 = 0;

   TRUNCATE TABLE dbo.bigtable;  

   SET IDENTITY_INSERT dbo.bigTable ON;
   INSERT INTO dbo.bigtable WITH (TABLOCK) (Id, c1, c2, c3)
   SELECT Id, c1, c2, c3 FROM dbo.bigtable_intermediate ORDER BY Id;
   SET IDENTITY_INSERT dbo.bigtable OFF;
ROLLBACK TRANSACTION