UPPER and LOWER in MySQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the UPPER() function do in MySQL?

The UPPER() function converts all letters in a string to uppercase letters.

beginner

What is the purpose of the LOWER() function in MySQL?

The LOWER() function converts all letters in a string to lowercase letters.

beginner

How would you convert the string 'Hello World' to all uppercase using MySQL?

Use the query: SELECT UPPER('Hello World'); which returns 'HELLO WORLD'.

beginner

How can you convert a column named 'name' to lowercase in a SELECT query?

Use: SELECT LOWER(name) FROM table_name; This returns the 'name' values all in lowercase.

intermediate

Why might you use UPPER() or LOWER() functions when comparing strings in SQL?

To make string comparisons case-insensitive by converting both strings to the same case before comparing.

What will SELECT UPPER('mysql') return?

A 'mysql'

B 'mYsQl'

C 'Mysql'

D 'MYSQL'

UPPER() converts all letters to uppercase, so 'mysql' becomes 'MYSQL'.

Which function converts all letters in a string to lowercase in MySQL?

A LOWCASE()

B UPPER()

C LOWER()

D TOLOWER()

LOWER() is the correct function to convert strings to lowercase.

How would you write a query to select all names in uppercase from a table called users?

A SELECT name FROM users WHERE UPPER(name);

B SELECT UPPER(name) FROM users;

C SELECT LOWER(name) FROM users;

D SELECT TOUPPER(name) FROM users;

SELECT UPPER(name) FROM users; converts the 'name' column values to uppercase.

If you want to compare two strings ignoring case, what should you do?

A Either A or B

B Use LOWER() on both strings before comparing

C Use UPPER() on both strings before comparing

D No need to change case

Converting both strings to the same case with UPPER() or LOWER() makes comparison case-insensitive.

What does SELECT LOWER('HELLO WORLD'); return?

A 'hello world'

B 'hElLo WoRlD'

C 'Hello World'

D 'HELLO WORLD'

LOWER() converts all letters to lowercase, so 'HELLO WORLD' becomes 'hello world'.

Explain how UPPER() and LOWER() functions work in MySQL and give an example of each.

Think about changing letter cases in words.

Why is it useful to use UPPER() or LOWER() when comparing text data in SQL?

Consider comparing 'Apple' and 'apple'.