Certain Dynamic Management Views(DMV)  return a sql_handle column . 

Examples of DMVs returning the sql_handle column are :

sys.dm_exec_query_stats

sys.dm_exec_requests

 sql_handle is a varbinary(64)  . A varbinary is suitable  for variable length binary data.  The sql_handle is a token referencing a stored procedure or batch.

The table-valued function sys.dm_exec_sql_text returns the text of the sql_handle. It has a parameter : @handle  (varbinary(64))

--returns sql query text referencing aggregate performance statistics

-- on sys.dm_exec_query_stats.

select sql_handle,(SELECT TOP 1 SUBSTRING(s2.text,statement_start_offset / 2+1 ,

      ( (CASE WHEN statement_end_offset = -1

         THEN (LEN(CONVERT(nvarchar(max),s2.text)) * 2)

         ELSE statement_end_offset END)  - statement_start_offset) / 2+1))  AS sql_statement from sys.dm_exec_query_stats

CROSS APPLY sys.dm_exec_sql_text(sql_handle) AS s2