T-SQL – John Huang's Blog

Len() and DataLength()

May 162013

Both system functions, Len() and DataLength(), in SQL Server are used to measure the length of the data. The main difference of those 2 is that Len() gets the string length of the data in which DataLength measures the storage length of the data.
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Truncate

Storage, T-SQL

Dec 232011

What are the differences between TRUNCATE and DELETE? You may immediately point out that:

Truncates reset the identity value
Truncates can’t have where clause
Truncates can’t be run on a table which is referenced by other tables
Truncates do not fire triggers.
Truncates can’t be run on a table which has depending objects such as indexed views.
Truncates can’t be run on a table which has published by merge or transactional replication publication
Truncates need db_owner and db_ddladmin permission.
Truncates need locks on the table and schema but do not need locks on rows of the tables