Truncate all tables in a SQL Server database

USE [DBNAME]
GO
DECLARE @tablename AS VARCHAR (1000)

DECLARE @sql AS VARCHAR (1000)

IF OBJECT_ID('tempdb.dbo.#tables') IS NOT NULL
    DROP TABLE #tables

SELECT *
INTO   #tables
FROM   sys.tables

WHILE EXISTS (SELECT * FROM   #tables)
    BEGIN
        SELECT @tablename = name
        FROM   #tables
        SELECT @sql = 'truncate table ' + @tablename;
        PRINT @sql
        EXECUTE (@sql)
        DELETE #tables
        WHERE  name = @tablename;
    END