In the previous post, I shared T-SQL script to generate a DeadLock situation in SQL Server Database.
In this post, I am sharing different scripts to detect a Deadlock in SQL Server.

1. Using SP_LOCK, you can find the WAIT status for blocking sessions:

SP_LOCK

2. Using sys.sysprocesses:

SELECT * FROM sys.sysprocesses 
WHERE blocked > 0

3. Using common DMV:

SELECT 	
	der.blocking_session_id AS BlockingSessionID
	,dest.text AS BlockingStatement
FROM sys.dm_exec_connections AS sdec
INNER JOIN sys.dm_exec_requests AS der
    ON sdec.session_id = der.blocking_session_id
INNER JOIN sys.dm_os_waiting_tasks AS dowt
    ON der.session_id = dowt.session_id
CROSS APPLY sys.dm_exec_sql_text(sdec.most_recent_sql_handle) AS dest

4. Using sys.dm_tran_locks:

SELECT 
	request_session_id AS SPID 
	,DB_NAME(resource_database_id) AS DatabaseName
	,resource_type AS LockedResource
	,request_mode AS LockType
FROM sys.dm_tran_locks

5. Enable required trace flags to log DeadLock related information in Tracefile:

DBCC TRACEON (1204, -1)
DBCC TRACEON (1222, -1)

6. Count total number of DeadLock:

SELECT cntr_value AS TotalNumberOfDeadLocks
FROM sys.dm_os_performance_counters
WHERE counter_name = 'Number of Deadlocks/sec'
   AND instance_name = '_Total'

7. Using Extended Events and below script to create Extended Event for monitoring the DeadLock:

CREATE EVENT SESSION [Deadlock_Monitor] ON SERVER 
ADD EVENT sqlos.scheduler_monitor_deadlock_ring_buffer_recorded,
ADD EVENT sqlserver.lock_deadlock,
ADD EVENT sqlserver.lock_deadlock_chain,
ADD EVENT sqlserver.xml_deadlock_report 
ADD TARGET package0.event_file(SET filename=N'C:\Temp\Deadlock_Monitor.xel')
WITH (MAX_MEMORY=4096 KB,EVENT_RETENTION_MODE=ALLOW_SINGLE_EVENT_LOSS,MAX_DISPATCH_LATENCY=30 SECONDS,MAX_EVENT_SIZE=0 KB,MEMORY_PARTITION_MODE=NONE,TRACK_CAUSALITY=OFF,STARTUP_STATE=ON)
GO

You can also use SSMS to create Extended Events for DeadLock, and you can monitor the live status of the server.

8. Using SQL Server Profiler:
SQL Server Profiler has three different events to capture a deadlock.

1.Deadlock graph
2.Lock: Deadlock
3.Lock: Deadlock Chain