SQL UPDATE and DELETE

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. Which statement changes Mia's grade to 'B' without affecting any other student?

A UPDATE Students SET grade = 'B' WHERE name = 'Mia';

B UPDATE Students SET grade = 'B';

2. What happens if you run DELETE FROM Orders; with no WHERE condition?

A Every record in the Orders table is deleted

B Only the last record in the Orders table is deleted

3. Which keyword is used to change the value in a field of existing records?

A CHANGE

B UPDATE

4. Which statement correctly removes only the record with StudentID 12?

A DELETE Students WHERE StudentID = 12;

B DELETE FROM Students WHERE StudentID = 12;

5. True or false: UPDATE Products SET price = 10; only changes one product.

A False: it sets the price of every product to 10

B True: UPDATE always changes just one record

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1UPDATE Students SET year = 10 WHERE id = 7;		AUPDATE Students SET email = 'sam@school.edu' WHERE id = 12;
2DELETE FROM Students WHERE id = 7;		BDELETE FROM Students;
3Change a student's email address, but only for the student with id 12		CFROM is missing. The correct syntax is DELETE FROM Students WHERE id = 7;
4Danger: leaving out WHERE deletes every record in the table		DChanges the year field to 10 for only the student whose id is 7
5UPDATE Students SET year = 10;		ERemoves only the record for the student whose id is 7
6DELETE Students WHERE id = 7;		FWHERE is missing, so every student's year is changed to 10. Add WHERE id = 7; to change just one record.

Definitions

UPDATE table SET field = value WHERE condition;

Fill in the Blanks

Complete each line of code by filling in the missing parts.

______ students SET year = 10 WHERE id = 3;

UPDATE students ___ year = 10 WHERE id = 3;

DELETE ____ students WHERE id = 7;

DELETE FROM students _____ id = 7;

UPDATE students SET year = 10 WHERE id _ 3;

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A UPDATE students

B SET year == 10

C WHERE id = 7;

Question 2

A DELETE FROM orders

B WHERE id = 12;

C UPDATE orders

D SET status = sent

E WHERE id = 15;

Question 3

A UPDATE pets

B SET age = 4

C WHERE id = 2;

D DELETE FROM pets;

Question 4

A UPDATE songs

B SET likes = 20

C WHEN title = 'Echo';

Question 5

A -- remove used tickets

B DELETE tickets

C WHERE used = 1;

Answer Key

SQL UPDATE and DELETE

Section A: Quick Questions

A — UPDATE Students SET grade = 'B' WHERE name = 'Mia';

A — Every record in the Orders table is deleted

B — UPDATE

B — DELETE FROM Students WHERE StudentID = 12;

A — False: it sets the price of every product to 10

Section B: Match the Pairs

UPDATE Students SET year = 10 WHERE id = 7; → Changes the year field to 10 for only the student whose id is 7

DELETE FROM Students WHERE id = 7; → Removes only the record for the student whose id is 7

Change a student's email address, but only for the student with id 12 → UPDATE Students SET email = 'sam@school.edu' WHERE id = 12;

Danger: leaving out WHERE deletes every record in the table → DELETE FROM Students;

UPDATE Students SET year = 10; → WHERE is missing, so every student's year is changed to 10. Add WHERE id = 7; to change just one record.

DELETE Students WHERE id = 7; → FROM is missing. The correct syntax is DELETE FROM Students WHERE id = 7;

Section C: Definitions

UPDATE table SET field = value WHERE condition; — UPDATE changes field values and DELETE FROM removes records. Always add WHERE so only the chosen records change. Without it, every record in the table is changed or deleted.

Section D: Fill in the Blanks

UPDATE students SET year = 10 WHERE id = 3;

DELETE FROM students WHERE id = 7;

UPDATE students SET year = 10
WHERE id = 3;

Section E: Spot the Error

B — SQL uses a single = to give a field its new value in SET. The line should be SET year = 10.

D — Text values must be in quotes. Without them, SQL treats sent as a field name. It should be SET status = 'sent'.

D — Leaving out WHERE deletes every record in the pets table. It should be DELETE FROM pets WHERE id = 9; so only one pet is removed.

C — The keyword that picks which records to change is WHERE, not WHEN. It should be WHERE title = 'Echo';

B — A DELETE statement needs the keyword FROM before the table name. It should be DELETE FROM tickets.