USE dbname;

GO

-- Truncate the log by changing the database recovery model to SIMPLE.

ALTER DATABASE dbname

SET RECOVERY SIMPLE;

GO

-- Shrink the truncated log file to 1 MB.

DBCC SHRINKFILE (2, 1);  -- here 2 is the file ID for trasaction log file,you can also mention the log file name (dbname_log)

GO

-- Reset the database recovery model.

ALTER DATABASE dbname

SET RECOVERY FULL;

GO