PostgreSQL STRING Functions Quiz: Test Your SQL Knowledge

Progress

True / False

In PostgreSQL, the length function can be used to determine the number of characters in a string.

True False

The length function returns the number of characters in a string.

True / False

The lower function in PostgreSQL converts all characters in a string to uppercase.

True False

The lower function converts all characters in a string to lowercase, not uppercase.

True / False

In PostgreSQL, the substring function extracts a substring from a string based on a specified start position and length.

True False

The substring function is used to extract a portion of a string starting from a specified position and for a specified length.

True / False

PostgreSQL's trim function removes both leading and trailing spaces from a string by default.

True False

The trim function removes leading and trailing spaces from a string unless specified otherwise.

True / False

The position function in PostgreSQL is used to find the position of the first occurrence of a substring within a string.

True False

The position function returns the position of the first occurrence of a substring within a string.

True / False

In PostgreSQL, the replace function can only replace a single character in a string.

True False

The replace function can replace all occurrences of a substring with another substring, not just a single character.

True / False

The regexp_replace function in PostgreSQL allows for replacing parts of a string using a regular expression pattern.

True False

The regexp_replace function uses regular expressions to match patterns in a string and replace them.

True / False

PostgreSQL's initcap function capitalizes the first letter of each word in a string and converts the rest to lowercase

True False

The initcap function capitalizes the first letter of each word in a string and converts all other letters to lowercase.

True / False

In PostgreSQL, the split_part function can split a string into an array based on a delimiter.

True False

The split_part function splits a string based on a delimiter and returns the specified part (it does not return an array, but a specific part of the split string).

Q10

True / False

PostgreSQL supports the to_ascii function, which can convert non-ASCII characters to their ASCII equivalents.

True False

The to_ascii function in PostgreSQL converts non-ASCII characters to their closest ASCII equivalents, useful for normalizing strings.

Q11

Single Choice

Which PostgreSQL function is used to convert a string to lowercase?

UPPER LOWER INITCAPLPAD

The LOWER() function in PostgreSQL is used to convert all characters in a string to lowercase.

Q12

Single Choice

What does the PostgreSQL function LENGTH('Hello World') return?

11 12 1314

The LENGTH() function returns the number of characters in a string. In this case, 'Hello World' has 11 characters.

Q13

Single Choice

Which PostgreSQL function concatenates two strings 'Post' and 'greSQL'?

CONCAT('Post', 'greSQL') CONCATENATE('Post', 'greSQL') MERGE('Post', 'greSQL')JOIN('Post', 'greSQL')

The CONCAT() function in PostgreSQL concatenates two or more strings together.

Q14

Single Choice

What is the output of the following PostgreSQL query?

SQL Code

SELECT SUBSTRING('PostgreSQL', 5, 4);

Post greS greS1tgre

The SUBSTRING() function extracts a substring starting at the 5th character and with a length of 4, resulting in 'greS'.

Q15

Single Choice

Which function removes all spaces from both ends of a string in PostgreSQL?

TRIM BTRIM RTRIMRTRIM

The TRIM() function removes all leading and trailing spaces from a string.

Q16

Single Choice

What is the result of the following PostgreSQL command?

SQL Code

SELECT POSITION('SQL' IN 'PostgreSQL Database');

5 7 108

The POSITION() function returns the location of a substring within a string. 'SQL' starts at the 10th position in 'PostgreSQL Database'.

Q17

Single Choice

How do you replace all occurrences of 'Post' with 'Pre' in the string 'PostgreSQL' using PostgreSQL?

SQL Code

SELECT REPLACE('PostgreSQL', 'Post', 'Pre');

PregreSQL PregreSQL` 0PreSQL

The REPLACE() function replaces all occurrences of a substring with another substring within a string.

Q18

Single Choice

What is the output of the following PostgreSQL query?

SQL Code

SELECT LPAD('SQL', 5, '*');

SQL** SQL **SQLSQL

The LPAD() function pads the string on the left side with a specified character to reach the desired length.

Q19

Single Choice

Which PostgreSQL function returns the number of bytes used to store the string 'PostgreSQL'?

LENGTH OCTET_LENGTH BYTE_LENGTHCHAR_LENGTH

The OCTET_LENGTH() function returns the number of bytes used to store the string in PostgreSQL.

Q20

Single Choice

What will be the result of the following PostgreSQL command?

SQL Code

SELECT INITCAP('postgresql string functions');

'Postgresql String Functions' PostGreSQL STRING FUNCTIONS' 'PostgreSQL String Functions'POSTGRESQL STRING FUNCTIONS'

The INITCAP() function capitalizes the first letter of each word in the string and converts the rest to lowercase.

Q21

Multiple Choice

Which SQL queries correctly use the CONCAT function to combine two columns in PostgreSQL?

SELECT CONCAT(first_name, ' ', last_name) AS full_name FROM users; SELECT CONCAT(first_name, last_name) AS full_name FROM users; SELECT first_name || ' ' || last_name AS full_name FROM users;SELECT first_name + ' ' + last_name AS full_name FROM users;

The CONCAT function is used to combine two or more strings in PostgreSQL. It can be used to concatenate columns directly or with additional strings.

Q22

Multiple Choice

Which SQL queries correctly use the SUBSTRING function to extract a portion of a string in PostgreSQL?

SELECT SUBSTRING(product_code, 4) AS code_number FROM products; SELECT SUBSTRING(product_code FROM 4) AS code_number FROM products; SELECT SUBSTRING(product_code FOR 4) AS code_number FROM products;SELECT SUBSTRING(product_code, 1, 3) AS code_number FROM products;

The SUBSTRING function is used to extract a portion of a string based on a specified starting position and length.

Q23

Multiple Choice

Which SQL queries correctly use the LENGTH function to determine the length of a string in PostgreSQL?

SELECT LENGTH(title) AS title_length FROM documents; SELECT CHAR_LENGTH(title) AS title_length FROM documents; SELECT LENGTH(title) FROM documents;SELECT LEN(title) AS title_length FROM documents;

The LENGTH function returns the number of characters in a string. It is useful for validating or manipulating string lengths.

Q24

Multiple Choice

Which SQL queries correctly use the TRIM function to remove spaces from a string in PostgreSQL?

SELECT TRIM(customer_name) AS trimmed_name FROM customers; SELECT TRIM(BOTH ' ' FROM customer_name) AS trimmed_name FROM customers; SELECT TRIM(LEADING ' ' FROM customer_name) AS trimmed_name FROM customers;SELECT TRIM(TRAILING ' ' FROM customer_name) AS trimmed_name FROM customers;

The TRIM function is used to remove spaces or other specified characters from the beginning and end of a string.

Q25

Multiple Choice

Which SQL queries correctly use the REPLACE function to modify strings in PostgreSQL?

SELECT REPLACE(phone_number, '(123)', '(321)') AS new_phone FROM employees; SELECT REPLACE(phone_number, '123', '321') AS new_phone FROM employees; SELECT REPLACE(phone_number, '(321)', '(123)') AS new_phone FROM employees;SELECT REPLACE(phone_number, '(123)', '(321)') FROM employees;

The REPLACE function is used to substitute all occurrences of a substring within a string with another substring.

Q26

Multiple Choice

Which SQL queries correctly use the INITCAP function to capitalize the first letter of each word in PostgreSQL?

SELECT INITCAP(book_title) AS capitalized_title FROM books; SELECT INITCAP(book_title) FROM books; SELECT INITCAP(UPPER(book_title)) AS capitalized_title FROM books;SELECT INITCAP(LOWER(book_title)) AS capitalized_title FROM books;

The INITCAP function capitalizes the first letter of each word in a string and converts all other letters to lowercase.

Q27

Multiple Choice

Which SQL queries correctly use the POSITION function to find the location of a substring in PostgreSQL?

SELECT POSITION('PostgreSQL' IN content) AS position FROM articles; SELECT POSITION('PostgreSQL' IN content) FROM articles; SELECT LOCATE('PostgreSQL', content) AS position FROM articles;SELECT CHARINDEX('PostgreSQL', content) AS position FROM articles;

The POSITION function returns the position of the first occurrence of a substring within a string.

Q28

Multiple Choice

Which SQL queries correctly use the LOWER and UPPER functions to change the case of strings in PostgreSQL?

SELECT LOWER(username) AS lower_username, UPPER(username) AS upper_username FROM users; SELECT LOWER(username), UPPER(username) FROM users; SELECT LOWER(username) AS lower_username FROM users;SELECT UPPER(username) AS upper_username FROM users;

The LOWER function converts all characters in a string to lowercase, and the UPPER function converts all characters to uppercase.

Q29

Multiple Choice

Which SQL queries correctly use the LPAD and RPAD functions to pad strings in PostgreSQL?

SELECT LPAD(account_id::text, 8, '0') AS padded_id FROM accounts; SELECT RPAD(account_id::text, 8, '0') AS padded_id FROM accounts; SELECT LPAD(account_id::text, 8) AS padded_id FROM accounts;SELECT RPAD(account_id::text, 8) AS padded_id FROM accounts;

The LPAD function pads the left side of a string with a specified character, while the RPAD function pads the right side.

Q30

Multiple Choice

Which SQL queries correctly use the SPLIT_PART function to split strings in PostgreSQL?

SELECT SPLIT_PART(email_address, '@', 1) AS username, SPLIT_PART(email_address, '@', 2) AS domain FROM emails; SELECT SPLIT_PART(email_address, '@', 1) AS username FROM emails; SELECT SPLIT_PART(email_address, '@', 2) AS domain FROM emails;SELECT SPLIT_PART(email_address, '@', 3) AS extra_part FROM emails;

The SPLIT_PART function splits a string into parts based on a delimiter and returns the specified part.

PostgreSQL Database Quiz Questions