sp_BlitzWho: Fix bugs found in full code review

Bug fixes:
- AND/OR precedence in >50GB memory check: The AND 50000000 < (...)
  condition only bound to the last OR branch (@ProductVersionMajor >= 13)
  due to operator precedence. SQL Server 2012 SP3+ and 2014 SP2+ always
  got MAX_GRANT_PERCENT = 1 regardless of server memory. Wrapped the
  version OR chain in parentheses so the memory check applies to all
  supported versions.
- AND/OR precedence in @ShowSleepingSPIDs=1: The bare OR clause
  short-circuited all preceding AND conditions (@@spid exclusion,
  host_name IS NOT NULL, AG read-only replica exclusion). Any session
  with an open transaction was returned unfiltered. Changed to
  AND (db_name IS NOT NULL OR open_tran >= 1) so base filters always
  apply.
- NOT IN with NULL r.database_id on AG servers: When r is NULL (sleeping
  sessions with no active request), NULL NOT IN (set) evaluates to
  UNKNOWN, silently excluding all sleeping sessions on servers with
  Always On read-only replicas. Added r.database_id IS NULL OR guard.
- Session waits TOP 5 ordered alphabetically: The @SessionWaitsSQL
  subquery used ORDER BY 1 which sorts by the concatenated string
  (alphabetically), not by wait time. Changed to
  ORDER BY SUM(waitwait.wait_time_ms) DESC to return the 5 longest
  waits, matching the dm_os_waiting_tasks subquery pattern.

Code quality:
- Removed unused variable @StringToSelect (declared but never referenced).
- Removed 4 redundant @ObjectFullName assignments (same value set 5
  consecutive times with no changes to inputs between them).

Tested: 12 execution scenarios on SQL2022 including default, Help,
ExpertMode, ShowSleepingSPIDs (0/1/2), Debug, MinElapsedSeconds filter,
SortOrder, GetOuterCommand, GetLiveQueryPlan, and ShowActualParameters.
All passed.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: erikdarlingdata

sp_BlitzWho.sql

@@ -93,7 +93,6 @@ DECLARE  @ProductVersion NVARCHAR(128) = CAST(SERVERPROPERTY('ProductVersion') A
 		,@AzureSQLDB BIT = (SELECT CASE WHEN SERVERPROPERTY('EngineEdition') = 5 THEN 1 ELSE 0 END)
 		,@EnhanceFlag BIT = 0
 		,@BlockingCheck NVARCHAR(MAX)
-		,@StringToSelect NVARCHAR(MAX)
 		,@StringToExecute NVARCHAR(MAX)
 		,@OutputTableCleanupDate DATE
 		,@SessionWaits BIT = 0
@@ -107,7 +106,7 @@ DECLARE  @ProductVersion NVARCHAR(128) = CAST(SERVERPROPERTY('ProductVersion') A
 												 WHERE  waitwait.session_id = wait.session_id
 												 GROUP BY  waitwait.wait_type
 												 HAVING SUM(waitwait.wait_time_ms) > 5
-												 ORDER BY 1												 
+												 ORDER BY SUM(waitwait.wait_time_ms) DESC
 												 FOR
 												 XML PATH('''') ) AS session_wait_info
 										FROM sys.dm_exec_session_wait_stats AS wait ) AS wt2
@@ -291,28 +290,24 @@ IF @OutputDatabaseName IS NOT NULL AND @OutputSchemaName IS NOT NULL AND @Output
 	EXEC(@StringToExecute);
 
 	/* If the table doesn't have the new cached_parameter_info computed column, add it. See Github #2842. */
-	SET @ObjectFullName = @OutputDatabaseName + N'.' + @OutputSchemaName + N'.' +  @OutputTableName;
 	SET @StringToExecute = N'IF NOT EXISTS (SELECT * FROM ' + @OutputDatabaseName + N'.sys.all_columns 
 		WHERE object_id = (OBJECT_ID(''' + @ObjectFullName + N''')) AND name = ''cached_parameter_info'')
 		ALTER TABLE ' + @ObjectFullName + N' ADD cached_parameter_info NVARCHAR(MAX) NULL;';
 	EXEC(@StringToExecute);
 
 	/* If the table doesn't have the new live_parameter_info computed column, add it. See Github #2842. */
-	SET @ObjectFullName = @OutputDatabaseName + N'.' + @OutputSchemaName + N'.' +  @OutputTableName;
 	SET @StringToExecute = N'IF NOT EXISTS (SELECT * FROM ' + @OutputDatabaseName + N'.sys.all_columns 
 		WHERE object_id = (OBJECT_ID(''' + @ObjectFullName + N''')) AND name = ''live_parameter_info'')
 		ALTER TABLE ' + @ObjectFullName + N' ADD live_parameter_info NVARCHAR(MAX) NULL;';
 	EXEC(@StringToExecute);
 
 	/* If the table doesn't have the new outer_command column, add it. See Github #2887. */
-	SET @ObjectFullName = @OutputDatabaseName + N'.' + @OutputSchemaName + N'.' +  @OutputTableName;
 	SET @StringToExecute = N'IF NOT EXISTS (SELECT * FROM ' + @OutputDatabaseName + N'.sys.all_columns 
 		WHERE object_id = (OBJECT_ID(''' + @ObjectFullName + N''')) AND name = ''outer_command'')
 		ALTER TABLE ' + @ObjectFullName + N' ADD outer_command NVARCHAR(4000) NULL;';
 	EXEC(@StringToExecute);
 
 	/* If the table doesn't have the new wait_resource column, add it. See Github #2970. */
-	SET @ObjectFullName = @OutputDatabaseName + N'.' + @OutputSchemaName + N'.' +  @OutputTableName;
 	SET @StringToExecute = N'IF NOT EXISTS (SELECT * FROM ' + @OutputDatabaseName + N'.sys.all_columns 
 		WHERE object_id = (OBJECT_ID(''' + @ObjectFullName + N''')) AND name = ''wait_resource'')
 		ALTER TABLE ' + @ObjectFullName + N' ADD wait_resource NVARCHAR(MAX) NULL;';
@@ -894,7 +889,7 @@ BEGIN
 				+ CASE WHEN @ShowSleepingSPIDs = 0 THEN
 						N' AND COALESCE(DB_NAME(r.database_id), DB_NAME(blocked.dbid)) IS NOT NULL'
 					  WHEN @ShowSleepingSPIDs = 1 THEN
-						N' OR COALESCE(r.open_transaction_count, blocked.open_tran) >= 1'
+						N' AND (COALESCE(DB_NAME(r.database_id), DB_NAME(blocked.dbid)) IS NOT NULL OR COALESCE(r.open_transaction_count, blocked.open_tran) >= 1)'
 					 ELSE N'' END;
 END /* IF @ProductVersionMajor > 9 and @ProductVersionMajor < 11 */
 
@@ -1195,12 +1190,12 @@ IF @ProductVersionMajor >= 11
 
 	    WHERE s.session_id <> @@SPID 
 	    AND s.host_name IS NOT NULL
-		AND r.database_id NOT IN (SELECT database_id FROM #WhoReadableDBs)
+		AND (r.database_id IS NULL OR r.database_id NOT IN (SELECT database_id FROM #WhoReadableDBs))
 	    '
 	    + CASE WHEN @ShowSleepingSPIDs = 0 THEN
 			    N' AND COALESCE(DB_NAME(r.database_id), DB_NAME(blocked.dbid)) IS NOT NULL'
 			    WHEN @ShowSleepingSPIDs = 1 THEN
-			    N' OR COALESCE(r.open_transaction_count, blocked.open_tran) >= 1'
+			    N' AND (COALESCE(DB_NAME(r.database_id), DB_NAME(blocked.dbid)) IS NOT NULL OR COALESCE(r.open_transaction_count, blocked.open_tran) >= 1)'
 			    ELSE N'' END;
 
 
@@ -1378,11 +1373,12 @@ ELSE
 	SET @StringToExecute = @BlockingCheck + N' SELECT  GETDATE() AS run_date , ' + @StringToExecute;
 
 /* If the server has > 50GB of memory, add a max grant hint to avoid getting a giant grant */
-IF (@ProductVersionMajor = 11 AND @ProductVersionMinor >= 6020)
-	OR (@ProductVersionMajor = 12 AND @ProductVersionMinor >= 5000 )
-	OR (@ProductVersionMajor >= 13 )
-	AND 50000000 < (SELECT cntr_value 			
-						FROM sys.dm_os_performance_counters 
+IF (   (@ProductVersionMajor = 11 AND @ProductVersionMinor >= 6020)
+    OR (@ProductVersionMajor = 12 AND @ProductVersionMinor >= 5000 )
+    OR (@ProductVersionMajor >= 13 )
+   )
+    AND 50000000 < (SELECT cntr_value
+						FROM sys.dm_os_performance_counters
 						WHERE object_name LIKE '%:Memory Manager%'
 						AND counter_name LIKE 'Target Server Memory (KB)%')
 	BEGIN