ESTIMATE( column-name [, value  [, relation-string ] ] )

REAL

This function returns selectivity estimates for the predicate column-name relation-string value. If value is NULL and the relation string is '=', the selectivity is for the predicate column-name IS NULL. If value is NULL and the relation string is '!=' or '<>', the selectivity is for the predicate column-name IS NOT NULL.

• Selectivity estimate sources
• Selectivity information in the graphical plan
• INDEX_ESTIMATE function [Miscellaneous]
• ESTIMATE_SOURCE function [Miscellaneous]
• EXPERIENCE_ESTIMATE function [Miscellaneous]

The following statement returns the percentage of EmployeeID values estimated to be greater than 200. The precise value depends on the actions you have carried out on the database.

SELECT FIRST ESTIMATE( EmployeeID, 200, '>' )
   FROM Employees
   ORDER BY 1;