use truncate statement. it has many adventages

Because truncate has not where clause and you need some data, then you can save them in another temp table, truncate base table and restore data.

for example

select * into #temp from TABLENAME where [ SOME CONDITION ]

truncate table TABLENAME

insert into TABLENAME select * From #temp

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But there are some restriction, you can't truncate table that participate in index view, are referenced by foreign key, if table is published by transactional replication e.t.c