SQL Reference Guide

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4. String Functions Reference

Most-used string functions.

CONCAT()

Return: Value

Concatenate strings.

Syntax signature:CONCAT(str1, str2)

Code snippet:

python

SELECT CONCAT(first_name, ' ', last_name) FROM users;

Expected Output:Full names list.

Remember: Always ensure correct syntax formatting when calling CONCAT().

UPPER()

Return: Value

Convert to uppercase.

Syntax signature:UPPER(str)

Code snippet:

python

SELECT UPPER(name) FROM users;

Expected Output:Uppercase names.

Remember: Always ensure correct syntax formatting when calling UPPER().

LOWER()

Return: Value

Convert to lowercase.

Syntax signature:LOWER(str)

Code snippet:

python

SELECT LOWER(email) FROM users;

Expected Output:Lowercase emails.

Remember: Always ensure correct syntax formatting when calling LOWER().

TRIM()

Return: Value

Strip leading/trailing spaces.

Syntax signature:TRIM(str)

Code snippet:

python

SELECT TRIM(code) FROM items;

Expected Output:Cleaned codes.

Remember: Always ensure correct syntax formatting when calling TRIM().

SUBSTRING()

Return: Value

Extract a substring.

Syntax signature:SUBSTRING(str, pos, len)

Code snippet:

python

SELECT SUBSTRING(phone, 1, 3) FROM users;

Expected Output:Phone area codes.

Remember: Always ensure correct syntax formatting when calling SUBSTRING().

REPLACE()

Return: Value

Substitute sub-strings.

Syntax signature:REPLACE(str, search, replace)

Code snippet:

python

SELECT REPLACE(url, 'http://', 'https://') FROM pages;

Expected Output:Secure URLs.

Remember: Always ensure correct syntax formatting when calling REPLACE().

LENGTH()

Return: Value

Count characters count.

Syntax signature:LENGTH(str)

Code snippet:

python

SELECT LENGTH(password) FROM accounts;

Expected Output:Password characters lengths.

Remember: Always ensure correct syntax formatting when calling LENGTH().

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