SQL Fundamentals

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Lab4 objectives100 XP

04.Undo a Mistake

You will make a mistake on purpose, inside a transaction, and then undo it.

Start a transaction. Then set every balance to 0 with one UPDATE that has no WHERE.
How many rows does account_log have now?
Undo the change. Every balance must be back and the transaction must be over.
Think before you run it: you run BEGIN;, add 25 to Sofia's balance, run COMMIT; and then ROLLBACK;. What is Sofia's balance at the end?

Something unclear, wrong or missing?

Databaselab-db · PostgreSQL in your browser 0:00

SELECT * FROM accounts;

Ctrl↵runs the query · select text to run part of it

Objective 1 of 40/4 done

Set every balance to 0, inside a transaction
Run BEGIN first, then an UPDATE with no WHERE.