Description
Most business data lives in relational databases, and SQL (Structured Query Language) is the standard way to retrieve and summarise it. Analysts use SQL to answer questions about sales, customers, and operations without waiting for engineers. Because employers expect this skill in almost every analyst role, a practical data analytics course gives SQL significant time.
Selecting and Filtering Data
Every analysis starts by choosing the right rows and columns. The SELECT, WHERE, and ORDER BY clauses handle this, and they form the foundation for everything else.
SELECT order_id, customer_id, amount
FROM orders
WHERE order_date >= '2026-01-01'
AND amount > 500
ORDER BY amount DESC;
This query returns large orders placed since January 2026, sorted from highest to lowest. Useful filtering tools include:
AND, OR, and NOT: Combine conditions.
IN and BETWEEN: Match lists and ranges.
LIKE: Search text patterns.
IS NULL: Find missing values.
