Why GROUP BY Happens Before SELECT🚨 This query fails. Why?

Why GROUP BY Happens Before SELECT

🚨 This query fails. Why?

SELECT Salary AS Sal
FROM Employee
GROUP BY Sal;
Step 1

Most beginners think:

SELECT runs first

Wrong ❌

Step 2

SQL Execution Order

FROM
WHERE
GROUP BY
HAVING
SELECT
ORDER BY
Step 3

When GROUP BY runs:

Alias doesn’t exist yet.

Because SELECT hasn’t executed.

Step 4

Correct Query

SELECT Salary AS Sal
FROM Employee
GROUP BY Salary;
Final Learning
You write SQL top-to-bottom.
SQL executes differently.

🔥 Understanding execution order is the shortcut to mastering SQL.

Видео Why GROUP BY Happens Before SELECT🚨 This query fails. Why? канала Mohammad Rahmatullah