Explanation:
Stack follows Last In First Out (LIFO) policy. Piling up of chairs one above the other is based on LIFO, people standing in a line is a queue and if the service is based on priority, then it can be associated with a priority queue. Tatkal Ticket Booking Follows First in First Out Policy. People who click the book now first will enter the booking page first.

Sorry I've forwarded it wrong, here is a complete post:

Common Data Structure Operations and
Array Sorting Algorithms

It could be useful to have it as a cheat sheet

SQL EXECUTION ORDER

SQL Doesn’t Run the Way You Think It Does!

Most people assume SQL runs top to bottom—
but in reality, the database follows a completely different process.

Here’s what actually happens when you hit Run:

🔹 FROM & JOIN – First, SQL figures out where to pull the data from.
🔹 WHERE – Then, it filters out rows that don’t match your conditions.
🔹 GROUP BY – If needed, it groups the remaining rows together.
🔹 HAVING – Now, it filters those groups (not individual rows).
🔹 SELECT – Finally, it picks the columns you asked for.
🔹 ORDER BY – It sorts the result.
🔹 LIMIT – At the very end, it restricts the output.

Why does this matter?
⤷ You can’t use column aliases in WHERE
because SELECT runs later.
⤷ Filtering after grouping (HAVING)
is less efficient than filtering before (WHERE).
⤷ Understanding this helps you write faster, better queries.

Most analysts assume SQL reads queries like English.
✅ But databases have their own logic—and mastering it makes
you a 10x better analyst!