Database Systems Final - SQL Basics

What is a schema

The structure and organization of the database

What is DDL

Data Definition Language - Defines schema (CREATE, ALTER, DROP)

What is DML

Data Manipulation Language - modifies data (SELECT, INSERT, UPDATE, DELETE)

What is DCL

Data Control Language - permissions (GRANT, REVOKE)

What is the order SQL processes clauses

FROM → WHERE → GROUP BY → HAVING → SELECT → ORDER BY

What are aggregate functions

COUNT, SUM, AVG, MIN, MAX

When must GROUP BY be used

When selecting non-aggregate columns with an aggregate

Order of precedence for SQL AND/OR/NOT

NOT → AND → OR

What does CREATE TABLE do

Defines a new table

What does ALTER TABLE do

Modifies and existing table

What does INSERT TABLE do

Adds new rows to a table

What does DELETE FROM do

Deletes rows in a table