6.1. Small Result Set, Direct Specific Criteria6.1.1. Index Usability6.1.2. Query Efficiency and Index Usage6.1.3. Data Dispersion6.1.4. Criterion Indexability6.2. Small Result Set, Indirect Criteria6.3. Small Intersection of Broad Criteria6.4. Small Intersection, Indirect Broad Criteria6.5. Large Result Set6.6. Self-Joins on One Table6.7. Result Set Obtained by Aggregation6.8. Simple or Range Searching on Dates6.8.1. Many Items, Few Historical Values6.8.1.1. Using subqueries6.8.1.2. Using OLAP functions6.8.2. Many Historical Values Per Item6.8.3. Current Values6.9. Result Set Predicated on Absence of Data