Basic Queries

Question 1

Queries

Answer 1

Allow us to communicate with the database by asking questions and having the result set return data relevant to the question.

Question 2

SELECT

Answer 2

Is used every time you want to query data from a database.

Question 3

FROM

Answer 3

Identifies the database schema from which data is being queried.

Question 4

AS

Answer 4

Is a keyword in SQL that allows you to rename a column or table using an alias.

Question 5

Distinct

Answer 5

When used will only return unique values. It filters out duplicate values.

Question 6

WHERE

Answer 6

Is a restricting statement. filters the result set to only include rows where the following condition is true.

Question 7

LIKE

Answer 7

is a special operator used with the WHERE clause to search for a specific pattern in a column. The pattern is up to the user to identify. Text conditions need ‘ ‘

Question 8

%

Answer 8

is a wildcard character that matches zero or more missing letters in the pattern.

Question 9

A%

Answer 9

matches all that with names that begin with letter ‘A’

Question 10

%a

Answer 10

matches all that end with ‘a’

Question 11

%a%

Answer 11

any value that contains the subject will return in the result.

Question 12

BETWEEN

Answer 12

operator can be used in a WHERE clause to filter the result set within a certain range. The values can be numbers, text or dates.BETWEEN two letters is not inclusive of the 2nd letter.
BETWEEN two numbers is inclusive of the 2nd number.

Question 13

AND

Answer 13

combines the two conditions. Used in conjunction with Where.

Question 14

OR

Answer 14

operator displays a row if any condition is true.

Question 15

Order By

Answer 15

Sorts the result.

Question 16

Limit

Answer 16

Don’t destroy the database.

Question 17

Case

Answer 17

A statement that allows us to create different outputs (usually in the SELECT statement). It is SQL’s way of handling if-then logic.

EX:
SELECT name,
 CASE
  WHEN imdb_rating > 8 THEN 'Fantastic'
  WHEN imdb_rating > 6 THEN 'Poorly Received'
  ELSE 'Avoid at All Costs'
 END
FROM movies;

Each WHEN tests a condition and the following THEN gives us the string if the condition is true.
The ELSE gives us the string if all the above conditions are false.
The CASE statement must end with END.