SQL Key Words

Question 1

What will you use for getting special column from a table?

Answer 1

SELECT

FROM

Question 2

How to tell SQL where the end of your query is?

Answer 2

;(semicolon)

Question 3

If you want to return a certain number of results, what can you use?

Answer 3

LIMIT

Question 4

If you want to select all the unique values from a column, what can you use?
If use Numpy, what can you use?

Answer 4

DISTINCT

numpy.unique(sequence)

Question 5

If you want to know how many rows in a table, what can you use?
How many non-missing values in a column, what can you use?

Answer 5

COUNT(*)

COUNT()

Question 6

If you want to filter based on both text and numeric values in a table, it is often with comparison operators and comes after the FROM, what can you use?

Answer 6

WHERE

Question 7

In SQL, what can you use for not equal operator? As per the SQL standard.

Answer 7

<>

Question 8

Which version of SQL you will use single quotes with WHERE, like ‘WHERE’?

Answer 8

PostgreSQL

Question 9

Using IOS date format, what January 22th,2008 will be?

Answer 9

‘2008-01-22’

Question 10

If you want to select data based on multiple conditions, what the keyword can you build up your WHERE queries by combining multiple conditions with?

Answer 10

AND

Question 11

What will you need to specify separately for every AND condition?

Answer 11

the column name
For example :
SELECT title
FROM films
WHERE release_year > 1991
AND release_year < 2008

Question 12

If you want to select rows that meet some but not all conditions, what will you use?

Answer 12

AND

OR

Question 13

Displaying rows that meet one of the specified conditions, what can you use?

Answer 13

OR

Question 14

What can you use alternatively like the following:
SELECT *
FROM people
WHERE age >= 10
AND age <= 14;

Answer 14

SELECT *
FROM people
WHERE age
BETWEEN 10 AND 14;

Question 15

Checking for range in SQL, what can you use?

It is not like range() in Python, cause it’s inclusive.

Answer 15

BETWEEN

Question 16

If you want to filter based on many conditions making it easier and quicker to specify multiple OR conditions, what can you use with WHERE?

Answer 16

IN

Question 17

In SQL, what represents a missing or unknown value?

Answer 17

NULL

Question 18

What expression can you use for checking NULL values?

What about not missing values?

Answer 18

IS NULL

IS NOT NULL

Question 19

To searching for a pattern in a column, what can you use in a WHERE clause?

Answer 19

LIKE

Question 20

To searching for a pattern in a column, what wildcard will match 0,1,or many characters in text?

Answer 20

%

Question 21

To searching for a pattern in a column, what wildcard will match a single character in text?

Answer 21

_

Question 22

SQL provides a few functions to perform some calculation on the data in a database, what’s its name?

Answer 22

Aggregate functions

Question 23

To get the average value from a column of table, what can you use?

Answer 23

AVG()

Question 24

To get the highest value from a column of table, what can you use?

Answer 24

MAX()

Question 25

To get the result of adding up the numeric values from a column of table, what can you use?

Answer 25

SUM()

Question 26

Using aggregate functions, you can perform basic arithmetic with symbols, what are they?

Answer 26

+ - * /

Question 27

To avoid using multiple same functions result, SQL allows you aliasing simply means you assign a temporary name to something. What can you use?

Answer 27

AS
Like ‘as’ keyword in Python:
import numpy as np

Question 28

In SQL, if you want to sort results in ascending or descending order according to the values of one or more columns, what keyword can be used?

Answer 28

ORDER BY

Question 29

By default ORDER BY will sort in ascending order. If you want to sort the results in descending order, what can you use?

Answer 29

DESC

Question 30

ORDER BY can be used to sort on multiple columns. What is important using it?

Answer 30

The order of columns.

Question 31

If you want to hybrid SELECT operation between string and numeric data type in SQL, what can you use?

Answer 31

GROUP BY

Question 32

What keyword always goes after the FROM clause?

Answer 32

GROUP BY

Question 33

When combining GROUP BY and ORDER BY. Make sure to always put the ORDER BY clause at the end of your query. Why ?

Answer 33

I can’t sort values that haven’t calculated yet!

Question 34

If you want to filter based on the result of an aggregate function, what can you use?

Answer 34

HAVING