Updating the statistics of all the tables regularly in your SQL Server Database is an integral part of Database Maintenance. This can be achieved in many ways. We can do this through a script or create a sql job scheduled to run at a certain time.
To determine whether an index has it's stats updated we can run the following command:
DBCC SHOW_STATISTICS (table_name , index_name)
To Update the Stats on a table the following command can be run :
UPDATE STATISTICS <table name> WITH FULLSCAN
The above command will scan all the rows of the table to get the updated statistics.
UPDATE STATISTICS <table name> WITH SAMPLE 50 PERCENT
The above script can be run for very large tables in case we want to specify a percentage of the total no of rows.