subqueries
Queries within queries
A subquery is a query nested inside another query in database programming.
The inner query runs first, and its results feed into the outer query: The subquery returns all customer IDs with orders over $500, then the main query pulls their contact information.
Subqueries can appear in SELECT, FROM, or WHERE clauses, enabling complex data retrieval in a single statement.
optimization
Coming into tangible existence
- flatteningReducing to evenness
- cachingTemporary local storage
- cost estimationPredicting future expenses
- cardinalitySize of a set
correlated
Mutually related statistically
- uncorrelatedLacking statistical relationship
materialization
Coming into tangible existence
- flatteningReducing to evenness
- cachingTemporary local storage
- cost estimationPredicting future expenses
running total
Sum recalculated after each addition
data extraction
Retrieving information from sources
- cross-referenceNotation pointing elsewhere
question, quest, sub, inquiry, query, questionable, inquire, inquisition, queries