de_notes

📚 LEFT & RIGHT

The LEFT and RIGHT functions are used in SQL to extract a specific number of characters from the start or end of a string.
They are useful for isolating prefixes, suffixes, or parts of codes.

---

🛠️ Basic Syntax

SELECT LEFT(column_name, number_of_characters)
FROM table_name;

SELECT RIGHT(column_name, number_of_characters)
FROM table_name;

• LEFT(column_name, n) returns the first n characters from the left.
• RIGHT(column_name, n) returns the last n characters from the right.

Example

SELECT LEFT(first_name, 3) AS name_start
FROM employees;

• This query extracts the first three letters of each employee's first name.

SELECT RIGHT(phone_number, 4) AS last_digits
FROM customers;

• This query extracts the last four digits of each customer's phone number.

Key Points

• Useful for slicing fixed-format strings (like IDs, phone numbers, or zip codes).
• Combined with TRIM, they can clean and then extract portions of strings.
• Make sure the column has enough characters to avoid unexpected empty results.

Additional Example

SELECT LEFT(product_code, 5) AS category_code
FROM products;

• This query extracts the first five characters from each product code to get the category code.

---

🎥 Video Notes

---

📝 Problem Description

Describe the problem, challenge, or topic discussed in a video related to SELECT FROM.
What concept was explained or what exercise was solved?

---

DataBase Given

---

💻 My SQL Code

-- Write your SQL code attempt or solution related to SQL COMMAND
SQL COMMAND

---

🧠 Solution Code / Explanation

SQL COMMAND

Explanation - Explain what you learned, any key takeaways, or how you solved the problem related to COMMAND._

---

⬅️ Previous: TRIM Next ➡️ UPPER & LOWER