SQL Troubleshooting Queries (2)

Found this MSSQL query on StackOverflow for troubleshooting locks or not being able to access a database being taken offline.. posting for self-reference:

SELECT
        DB_NAME(l.resource_database_id) DB,
	l.resource_type,
	l.request_mode,
	l.request_status,
	l.request_session_id,
	r.command,
	r.status,
	r.blocking_session_id,
	r.wait_type,
	r.wait_time,
	r.wait_resource,
	request_sql_text = st.text,
	s.program_name,
	most_recent_sql_text = stc.text
FROM sys.dm_tran_locks l
LEFT JOIN sys.dm_exec_requests r
	ON l.request_session_id = r.session_id
LEFT JOIN sys.dm_exec_sessions s
	ON l.request_session_id = s.session_id
LEFT JOIN sys.dm_exec_connections c
	ON s.session_id = c.session_id
OUTER APPLY sys.dm_exec_sql_text(r.sql_handle) st
OUTER APPLY sys.dm_exec_sql_text(c.most_recent_sql_handle) stc
--WHERE l.resource_database_id = DB_ID('[Database Name]')
ORDER BY request_session_id;

Some additional helpful links:
Lock Modes
Wait Types; Additional wait Type Info
Locks System Table Info

Also, connection by session:

SELECT * FROM SYS.DM_EXEC_CONNECTIONS WHERE SESSION_ID = [SESSION ID]