Basic Retrieval Queries

Flashcards covering basic retrieval queries, SQL syntax, and aggregate functions.

SELECT statement

For retrieving information from a database. Includes SELECT, FROM, and WHERE clauses.

Select * from …

A list of attribute names whose values are to be retrieved by the query.

Relation List

A list of the relation names required to process the query.

Select condition

A conditional (Boolean) expression that identifies the tuples to be retrieved by the query.

WHERE

Used to specify a condition for row selection in a query.

GROUP BY clause

Used to divide a relation into subsets of tuples based on grouping attribute(s).

HAVING clause

Provides a condition to select or reject an entire group; applied after the WHERE clause.

IN

Used for comparison of a value with a set of values.

Aliasing

Alternative relation names used to refer to the same relation multiple times in a query.

Asterisk (*)

Retrieves all the attribute values of the selected tuples.

DISTINCT

Keyword used in the SELECT clause to eliminate duplicate tuples in query results.

Aggregate Functions

COUNT, SUM, MAX, MIN, and AVG