Updating two tables in sql
You can look at the header using DBCC SHOW_STATISTICS. They’re also sampled and automated to update on the criteria that we outlined in the first question.
Grant Fritchey answers the 18 most frequently-asked questions about SQL Server Statistics: the ones we somehow feel silly asking in public, and think twice about doing so.
So, yes, even the automatically-created statistics get updated and maintained as the data changes.
The statistics themselves are stored within your database in a series of internal tables that include sysindexes. The density is a set of rows with only three columns, equal in the number of rows to the number of columns defining the key columns of the statistic. The histogram is up to 200 rows and never exceeds that amount.
In this situation, the statistics can get stale or be inaccurate. This should be an exceptional event in most systems.
SQL Server provides two basic commands to help you to maintain your statistics, sp_updatestats and UPDATE STATISTICS.
If you absolutely must update the statistics and rebuild the indexes and you’re not going to try to tightly control exactly which indexes and tables you do this on, then the best practice would be to update the statistics first and then rebuild the indexes second. The keyword and tricky phrase that you have to look at is WITH FULL SCAN.