RANGE CONDITION FOR KEY is a search strategy of the SQL optimizer.
When Can the System Use This Strategy?
The database system searches the specified range of the table sequentially. To restrict the range, the system sets a start and a stop key.
How Does the System Access the Data?
The database system uses this search strategy if one of the following conditions is met:
For the first k columns of the primary key, equality conditions were specified ( 1 ≤ k < n, n= number of key columns). All other key columns were either not specified at all or were specified with a range condition.
The first key column was specified with a range condition.
The values of an IN condition are very close together.