SQL Basic Functions

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💻 Introduction

SQL provides a variety of built-in functions to manipulate string, number, and date data types. These functions simplify calculations and formatting tasks.

1️⃣ String Functions

-- Convert to uppercase
SELECT UPPER('retailcoder');

-- Convert to lowercase
SELECT LOWER('RETAILCODER');

-- Get length of string
SELECT LENGTH('RetailCoder');

2️⃣ Number Functions

-- Round a number
SELECT ROUND(123.4567, 2);

-- Get absolute value
SELECT ABS(-25);

3️⃣ Date / Time Functions

-- Current timestamp
SELECT NOW();

-- Extract year
SELECT EXTRACT(YEAR FROM CURRENT_DATE);
Tip: These functions can be combined in queries to calculate, format, and filter data efficiently.

✅ Key Takeaways

  • String functions: UPPER, LOWER, LENGTH
  • Number functions: ROUND, ABS
  • Date functions: NOW(), EXTRACT()
  • Use functions inside SELECT, WHERE, or ORDER BY clauses

📚 Continue Learning

💬 Got questions on SQL functions? Drop them in the comments!




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