sp_BlitzWho checking for 1900

For invalid query start times that cause overflows. Closes #3243.

Author: BrentOzar

sp_BlitzWho.sql

@@ -676,7 +676,7 @@ BEGIN
     /* Think of the StringToExecute as starting with this, but we'll set this up later depending on whether we're doing an insert or a select:
     SELECT @StringToExecute = N'SELECT  GETDATE() AS run_date ,
     */
-    SET @StringToExecute = N'COALESCE( RIGHT(''00'' + CONVERT(VARCHAR(20), (ABS(r.total_elapsed_time) / 1000) / 86400), 2) + '':'' + CONVERT(VARCHAR(20), (DATEADD(SECOND, (r.total_elapsed_time / 1000), 0) + DATEADD(MILLISECOND, (r.total_elapsed_time % 1000), 0)), 114), RIGHT(''00'' + CONVERT(VARCHAR(20), DATEDIFF(SECOND, s.last_request_start_time, GETDATE()) / 86400), 2) + '':'' + CONVERT(VARCHAR(20), DATEADD(SECOND, DATEDIFF(SECOND, s.last_request_start_time, GETDATE()), 0), 114) ) AS [elapsed_time] ,
+    SET @StringToExecute = N' CASE WHEN YEAR(s.last_request_start_time) = 1900 THEN NULL ELSE COALESCE( RIGHT(''00'' + CONVERT(VARCHAR(20), (ABS(r.total_elapsed_time) / 1000) / 86400), 2) + '':'' + CONVERT(VARCHAR(20), (DATEADD(SECOND, (r.total_elapsed_time / 1000), 0) + DATEADD(MILLISECOND, (r.total_elapsed_time % 1000), 0)), 114), RIGHT(''00'' + CONVERT(VARCHAR(20), DATEDIFF(SECOND, s.last_request_start_time, GETDATE()) / 86400), 2) + '':'' + CONVERT(VARCHAR(20), DATEADD(SECOND, DATEDIFF(SECOND, s.last_request_start_time, GETDATE()), 0), 114) ) END AS [elapsed_time] ,
 			       s.session_id ,
 					CASE WHEN r.blocking_session_id <> 0 AND blocked.session_id IS NULL 
 							THEN r.blocking_session_id
@@ -894,7 +894,7 @@ IF @ProductVersionMajor >= 11
     /* Think of the StringToExecute as starting with this, but we'll set this up later depending on whether we're doing an insert or a select:
     SELECT @StringToExecute = N'SELECT  GETDATE() AS run_date ,
     */
-    SELECT @StringToExecute = N'COALESCE( RIGHT(''00'' + CONVERT(VARCHAR(20), (ABS(r.total_elapsed_time) / 1000) / 86400), 2) + '':'' + CONVERT(VARCHAR(20), (DATEADD(SECOND, (r.total_elapsed_time / 1000), 0) + DATEADD(MILLISECOND, (r.total_elapsed_time % 1000), 0)), 114), RIGHT(''00'' + CONVERT(VARCHAR(20), DATEDIFF(SECOND, s.last_request_start_time, GETDATE()) / 86400), 2) + '':'' + CONVERT(VARCHAR(20), DATEADD(SECOND, DATEDIFF(SECOND, s.last_request_start_time, GETDATE()), 0), 114) ) AS [elapsed_time] ,
+    SELECT @StringToExecute = N' CASE WHEN YEAR(s.last_request_start_time) = 1900 THEN NULL ELSE COALESCE( RIGHT(''00'' + CONVERT(VARCHAR(20), (ABS(r.total_elapsed_time) / 1000) / 86400), 2) + '':'' + CONVERT(VARCHAR(20), (DATEADD(SECOND, (r.total_elapsed_time / 1000), 0) + DATEADD(MILLISECOND, (r.total_elapsed_time % 1000), 0)), 114), RIGHT(''00'' + CONVERT(VARCHAR(20), DATEDIFF(SECOND, s.last_request_start_time, GETDATE()) / 86400), 2) + '':'' + CONVERT(VARCHAR(20), DATEADD(SECOND, DATEDIFF(SECOND, s.last_request_start_time, GETDATE()), 0), 114) ) END AS [elapsed_time] ,
 			       s.session_id ,
 					CASE WHEN r.blocking_session_id <> 0 AND blocked.session_id IS NULL 
 					THEN r.blocking_session_id