INDEX_ESTIMATE function [Miscellaneous]

This function is the same as the ESTIMATE function, except that it always looks only in an index.

Syntax 
INDEX_ESTIMATE( column-name, number
[ , relation-string ] 
)
Parameters

  • column-name   The name of the column that is used in the estimate.

  • number   If number is specified, the function returns as a REAL the percentage estimate that the query optimizer uses.

  • relation-string   The comparison operator used for the comparison, enclosed in single quotes. Possible values for this parameter are: '=' , '>' , '<' , '>=' , '<=' , '<>' , '!=' , '!<' , and '!>'. The default is '='.

Remarks

If value is NULL then the relation strings '=' and '!=' are interpreted as the IS NULL and IS NOT NULL conditions, respectively.

See also
Standards and compatibility

  • SQL/2003   Vendor extension.

Example

The following statement returns the value 89.4736862183.

SELECT FIRST ESTIMATE( EmployeeID, 200, '>' )
FROM Employees;
Copyright © 2008, iAnywhere Solutions, Inc. - SQL Anywhere 11.0.0