Now, let's move to the next topic of data analytics roadmap:

SQL Basics for Data Analytics

What SQL does
- Pull data from databases
- Filter large datasets
- Combine tables
- Summarize metrics

Core clauses
- SELECT: Choose columns
Example: SELECT name, sales FROM orders;
- FROM: Source table
Example: FROM orders;
- WHERE: Filter rows
Example: WHERE sales > 5000;
- ORDER BY: Sort results
Example: ORDER BY sales DESC;
- LIMIT: Restrict rows
Example: LIMIT 10;

Filtering operators
- =, <>, >, <, >=, <=
- BETWEEN for ranges
- IN for lists
- LIKE for patterns
Example: WHERE region IN ('East','West');

Logical conditions
- AND
- OR
- NOT

Aggregations
- GROUP BY: Group rows
Example: GROUP BY product;
- Aggregate functions: COUNT, SUM, AVG, MIN, MAX
- HAVING: Filter after aggregation
Example: HAVING SUM(sales) > 100000;

JOINS
- INNER JOIN: Matching rows only
- LEFT JOIN: All left rows, matching right
- RIGHT JOIN: All right rows, matching left
- FULL JOIN: All rows from both tables
Example:

SELECT o.order_id, c.customer_name 
FROM orders o 
INNER JOIN customers c 
ON o.customer_id = c.customer_id;

NULL handling
- IS NULL
- IS NOT NULL
- COALESCE(column, 0)

Subqueries
Query inside a query
Example:

SELECT * 
FROM orders 
WHERE sales > (SELECT AVG(sales) FROM orders);

Window functions
- ROW_NUMBER: Unique row number
- RANK: Ranking with gaps
- PARTITION BY: Reset calculation per group
Example:
ROW_NUMBER() OVER (PARTITION BY department ORDER BY salary DESC)

Common mistakes
- Forgetting GROUP BY columns
- Using WHERE instead of HAVING
- Wrong join condition
- Ignoring NULLs

Daily practice
- Write 5 SELECT queries
- Use 1 JOIN
- Use 1 GROUP BY
- Handle NULL values

SQL Resources: https://whatsapp.com/channel/0029VanC5rODzgT6TiTGoa1v

Double Tap ♥️ For More