SQL

Question 1

SQL

Answer 1

Structured Query Language

Question 2

RDBMS

Answer 2

Relational Database Management System

Question 3

Lets you add columns to a table in a database

Answer 3

ALTER TABLE

ALTER TABLE table_name
ADD column datatype;

Question 4

Is an operator that combines two conditions. Both conditions must be true for the row to be included in the result set

Answer 4

AND

SELECT column_name(s)
FROM table_name
WHERE column_1 = value_1 AND column_2 = value_2;

Question 5

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

Answer 5

AS

SELECT column_name AS ‘Alias’
FROM table_name;

Question 6

Is an aggregate function that returns the average value for a numeric column.

Answer 6

AVG

SELECT AVG(column\_name)
FROM table\_name;

Question 7

The _____ operator is used to filter the result set within a certain range. The values can be numbers, text or dates.

Answer 7

BETWEEN

SELECT column_name(s)
FROM table_name
WHERE column_name BETWEEN value_1 AND value_2;

Question 8

Is a function that takes the name of a column as an argument and counts the number of rows where the column is not NULL.

Answer 8

COUNT

SELECT COUNT(column\_name)
FROM table\_name;

Question 9

Creates a new table in the database. It allows you to specify the name of the table and the name of each column in the table.

Answer 9

CREATE TABLE

CREATE TABLE table_name (
column_1 datatype,
column_2 datatype,
column_3 datatype
);

Question 10

Is used to remove rows from a table.

Answer 10

DELETE

DELETE FROM table_name
WHERE some_column = some_value;

Question 11

Is a clause in SQL that is only used with aggregate functions. It is used in collaboration with the SELECT statement to arrange identical data into groups.

Answer 11

GROUP BY

SELECT COUNT(*)
FROM table_name
GROUP BY column_name;

Question 12

Will combine rows from different tables if the join condition is true.

Answer 12

INNER JOIN

SELECT column_name(s)
FROM table_1
JOIN table_2
ON table_1.column_name = table_2.column_name;

Question 13

Is used to add a new row to a table.

Answer 13

INSERT

INSERT INTO table_name (column_1, column_2, column_3)
VALUES (value_1, ‘value_2’, value_3);

Question 14

Is a special operator used with the WHERE clause to search for a specific pattern in a column.

Answer 14

LIKE

SELECT column_name(s)
FROM table_name
WHERE column_name LIKE pattern;

Question 15

Is a clause that lets you specify the maximum number of rows the result set will have.

Answer 15

LIMIT

SELECT column_name(s)
FROM table_name
LIMIT number;

Question 16

Is a function that takes the name of a column as an argument and returns the largest value in that column.

Answer 16

MAX

SELECT MAX(column\_name)
FROM table\_name;

Question 17

Is a function that takes the name of a column as an argument and returns the smallest value in that column.

Answer 17

MIN

SELECT MIN(column\_name)
FROM table\_name;

Question 18

Is an operator that filters the result set to only include rows where either condition is true.

Answer 18

OR

SELECT column_name
FROM table_name
WHERE column_name = value_1
OR column_name = value_2;

Question 19

Is a clause that indicates you want to sort the result set by a particular column either alphabetically or numerically.

Answer 19

ORDER BY

SELECT column_name
FROM table_name
ORDER BY column_name ASC|DESC;

Question 20

Will combine rows from different tables even if the the join condition is not met. Every row in the left table is returned in the result set, and if the join condition is not met, then NULL values are used to fill in the columns from the right table.

Answer 20

OUTER JOIN

SELECT column_name(s) FROM table_1
LEFT JOIN table_2
ON table_1.column_name = table_2.column_name;

Question 21

Is a function that takes a column name and an integer as an argument. It rounds the values in the column to the number of decimal places specified by the integer.

Answer 21

ROUND

SELECT ROUND(column\_name, integer)
FROM table\_name;

Question 22

Specifies that the statement is going to be a query that returns unique values in the specified column(s).

Answer 22

SELECT DISTINCT

SELECT DISTINCT column_name FROM table_name;

Question 23

Is a function that takes the name of a column as an argument and returns the sum of all the values in that column.

Answer 23

SUM

SELECT SUM(column\_name)
FROM table\_name;

Question 24

Allows you to edit rows in a table.

Answer 24

UPDATE

UPDATE table_name
SET some_column = some_value
WHERE some_column = some_value;

Question 25

Is a clause that indicates you want to filter the result set to include only rows where the following condition is true.

Answer 25

WHERE

SELECT column_name(s)
FROM table_name
WHERE column_name operator value;