UPDATE and DELETE Commands

UPDATE — Change Data

UPDATE students SET marks = 95 WHERE roll_no = 1;

DELETE — Remove Rows

DELETE FROM students WHERE roll_no = 5;

Deletes the row(s) matching the condition.

The Most Important Rule

Summary

• UPDATE changes existing rows; DELETE removes rows.
• Always add WHERE, or the whole table is affected.

UPDATE — Data बदलें

UPDATE students SET marks = 95 WHERE roll_no = 1;

DELETE — Rows हटाएं

DELETE FROM students WHERE roll_no = 5;

Condition से match करने वाली row(s) delete करता है।

सबसे ज़रूरी नियम

सारांश

• UPDATE मौजूदा rows बदलता है; DELETE rows हटाता है।
• हमेशा WHERE लगाएं, वरना पूरी table प्रभावित होती है।