INDEX MERGE ORDERING

摘要

Method to order query results, by processing a received query at least in part using a composite key index, wherein the composite key index comprises at least two key columns, wherein the at least two key columns comprise at least one pre-ordering column and an ordering column, wherein the query specifies ordering criteria to order a result set based on values of the ordering column, wherein the processing comprises receiving, from the composite key index, an ordering column value for each unique pre-ordering column value in the composite key index, identifying a first ordering column value as being ordered first according to the ordering criteria, and returning the first ordering column value as being responsive to the query.

主权项

1. A method to order query results, comprising:
processing a received query at least in part using a composite key index, wherein the composite key index comprises at least two key columns, wherein the at least two key columns comprise at least one pre-ordering column and an ordering column, wherein the query specifies ordering criteria to order a result set based on values of the ordering column, by:
receiving, from the composite key index, an ordering column value for each unique pre-ordering column value in the composite key index;identifying a first ordering column value as being ordered first according to the ordering criteria; andreturning the first ordering column value as being responsive to the query.