W3. SQL Syntax

Question 1

Q: What are SQL statements?

Answer 1

A: Actions performed on a database, made up of easy-to-understand keywords.

Question 2

Q: Provide an example SQL statement to select all records from the “Customers” table.

Answer 2

A: SELECT * FROM Customers;

Question 3

Q: What is a database table?

Answer 3

A: A structure that holds data in rows (records) and columns (fields), identified by a unique name (e.g., “Customers”).

Question 4

Q: In the “Customers” table, what are some examples of columns (fields)?

Answer 4

A: CustomerID, CustomerName, ContactName, Address, City, PostalCode, and Country.

Question 5

Q: How many records are shown in the “Customers” example table?

Answer 5

A: Five records, one for each customer.

Question 6

Q: Are SQL keywords case-sensitive?

Answer 6

A: No, SQL keywords are not case-sensitive (e.g., select is the same as SELECT).

Question 7

Q: Why might a semicolon be used at the end of an SQL statement?

Answer 7

A: To separate multiple SQL statements when executed in the same call; it’s standard in some database systems.

Question 8

Q: List some of the most important SQL commands and their functions.

Answer 8

SELECT - extracts data
UPDATE - updates data
DELETE - deletes data
INSERT INTO - inserts new data
CREATE DATABASE - creates a new database
ALTER DATABASE - modifies a database
CREATE TABLE - creates a new table
ALTER TABLE - modifies a table
DROP TABLE - deletes a table
CREATE INDEX - creates an index
DROP INDEX - deletes an index