To observe statistics on a table, we use the help
stats command. This gives an overview of stats collected on the table level:
/*Help statistics*/ HELP STATISTICS ON web_clicks; Date Time Unique Values Column Names ‐‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ 17/07/07 10:49:55 100 * (represent number of rows in table) 17/07/07 10:49:55 100 date
Date Time
: Represents the date and time of stats collected. Helps to identify how old stats are.Unique Values
: Number of unique values for a column, or combination of columns, in case of multi-column stats.Column Name
: Name of the column on which stats are collected. TheHELP STATISTICS
command is enhanced to show the expression statistics. It shows the name given to the expression statistics instead of the actual expressions.
Following is the most popular diagnostic command. It will give you suggestions on stats that need to be collected...