Chapter 5

Question 1

Aggregate Functions

Answer 1

For calculating and summarizing values in queries, SQL provides the following aggregate functions:

• COUNT
• SUM
• AVG
• MIN
• MAX

Question 2

Alias

Answer 2

A name that is not one’s true name

Question 3

COUNT

Answer 3

returns the number of cells in a range that contains numbers

Question 4

CREATE TABLE

Answer 4

Used for creating and connecting relational tables

Question 5

CREATE VIEW

Answer 5

In SQL, a view is a virtual table based on the result-set of an SQL statement. A view contains rows and columns, just like a real table. The fields in a view are fields from one or more real tables in the database. You can add SQL functions, WHERE, and JOIN statements to a view and present the data as if the data were coming from one single table.

CREATE VIEW view_name AS
SELECT column_name(s)
FROM table_name
WHERE condition

Question 6

Data Control Language

Answer 6

Used for data access control

Question 7

Data Manipulation Language

Answer 7

Used to insert, modify, delete, and retrieve data

• Example commands
  
  • insert into
  • update
  • delete
  • select

Question 8

Data Definition Language

Answer 8

Used to create and modify the structure of the database:

• create
• alter
• drop

Question 9

DELETE

Answer 9

to erase, wipe out, cut out

Question 10

DROP TABLE

Answer 10

Used to remove a table from the database

Question 11

INSERT INTO

Answer 11

used to populate the created relations with data

Question 12

SELECT

Answer 12

used for the retrieval of data from the database relations

• most commonly issued SQL statement
• Basic form:
  
  • SELECT <columns></columns>
  • FROM <table>

Question 13

DISTINCT

Answer 13

Can be used in conjunction with the SELECT statement

Question 14

ORDER BY

Answer 14

Used to sort the results of the query by one or more columns (for expressions)

Question 15

LIKE

Answer 15

Used for retrieval of records whose values partially match a certain criteria

Question 16

Query

Answer 16

automatically execute SQL statements as soon as a page or widget loads

Question 17

SQL Data Types

Answer 17

Each column of each SQL created relation has a specified data type

• CHAR
• VARCHAR
• INT
• NUMERIC
• DATE

Question 18

SQL Standard

Answer 18

SQL became the standard language for querying data contained in the relational database

Question 19

SUM

Answer 19

an Aggregate Function used to find the sum of all non-NULL values in a column

Question 20

UPDATE

Answer 20

allows you to change the values in records using the UPDATE SQL command

Question 21

VIEW

Answer 21

a SQLite statement that is stored in the database with an associated name

Question 22

WHERE

Answer 22

used to specify a condition while fetching the data from one table or multiple tables