[Solved] Truncate (Delete) data from all Tables present in database using single query in SQL Server

You can use the sp_MSforeachtable stored procedure like so:

USE MyDatabase
EXEC sp_MSforeachtable 'TRUNCATE TABLE ?'

Be warned that this will delete (by truncation) ALL data from all user tables. And in case you can't TRUNCATE due to foreign keys etc. you can run the same as a delete: