UPDATE multiple columns in SQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to update the salary column to 5000.

SQL

UPDATE employees SET salary = [1] WHERE id = 3;

Drag options to blanks, or click blank then click option'

Asalary

B'5000'

C5000

DNULL

Attempts:

3 left

💡 Hint

Common Mistakes

Putting quotes around numbers causing type errors.

Using column name instead of a value.

The salary column should be set to the numeric value 5000 without quotes.

2fill in blank

medium

Complete the code to update the name column to 'Alice'.

SQL

UPDATE employees SET name = [1] WHERE id = 1;

Drag options to blanks, or click blank then click option'

A'Alice'

BAlice

C"Alice"

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around string values.

Using double quotes instead of single quotes.

String values in SQL must be enclosed in single quotes.

3fill in blank

hard

Fix the error in the code to update both name and salary columns.

SQL

UPDATE employees SET name = 'Bob', salary = [1] WHERE id = 2;

Drag options to blanks, or click blank then click option'

ANULL

B6000

Csalary

D'6000'

Attempts:

3 left

💡 Hint

Common Mistakes

Using quotes around numeric values causing errors.

Using column names instead of values.

Numeric values should not be in quotes when updating numeric columns.

4fill in blank

hard

Fill both blanks to update name to 'Carol' and salary to 7000.

SQL

UPDATE employees SET name = [1], salary = [2] WHERE id = 4;

Drag options to blanks, or click blank then click option'

A'Carol'

B7000

C'7000'

DCarol

Attempts:

3 left

💡 Hint

Common Mistakes

Using quotes around numbers.

Forgetting quotes around strings.

Strings need single quotes; numbers do not.

5fill in blank

hard

Fill all three blanks to update name to 'Dave', salary to 8000, and department to 'Sales'.

SQL

UPDATE employees SET name = [1], salary = [2], department = [3] WHERE id = 5;

Drag options to blanks, or click blank then click option'

A'Dave'

B8000

C'Sales'

DSales

Attempts:

3 left

💡 Hint

Common Mistakes

Using quotes around numbers.

Forgetting quotes around strings.

Using unquoted strings causing syntax errors.

Strings must be in single quotes; numbers must not.

Practice

1. What does the SQL UPDATE statement do when you specify multiple columns in the SET clause?

easy

A. It deletes the rows that match the condition.

B. It only updates the first column listed and ignores the rest.

C. It creates new rows with the specified column values.

D. It changes the values of all specified columns in the selected rows.

Solution

1. Step 1: Understand the UPDATE statement

   The UPDATE statement modifies existing rows in a table.

2. Step 2: Effect of multiple columns in SET clause

   When multiple columns are listed in SET, all those columns are updated in the rows that match the WHERE condition.

3. Final Answer:

   It changes the values of all specified columns in the selected rows. -> Option D

4. Quick Check:

   UPDATE with multiple columns updates all listed columns [OK]

Hint: SET updates all listed columns together [OK]

Common Mistakes:

• Thinking UPDATE adds new rows
• Believing UPDATE deletes rows
• Assuming only first column updates

2. Which of the following is the correct syntax to update two columns, price and stock, in a table named products?

easy

A. UPDATE products SET price = 10, stock = 50 WHERE id = 1;

B. UPDATE products (price = 10, stock = 50) WHERE id = 1;

C. UPDATE products SET (price, stock) = (10, 50) WHERE id = 1;

D. UPDATE products WHERE id = 1 SET price = 10, stock = 50;

Solution

1. Step 1: Recall correct UPDATE syntax

   The correct syntax is UPDATE table_name SET column1 = value1, column2 = value2 WHERE condition;

2. Step 2: Check each option

   UPDATE products SET price = 10, stock = 50 WHERE id = 1; matches the correct syntax exactly. The other options have syntax errors.

3. Final Answer:

   UPDATE products SET price = 10, stock = 50 WHERE id = 1; -> Option A

4. Quick Check:

   SET column = value pairs separated by commas [OK]

Hint: Use SET column=value, column=value syntax [OK]

Common Mistakes:

• Using parentheses incorrectly in SET clause
• Placing WHERE before SET
• Missing commas between column assignments

3. Given the table employees with columns salary and bonus, what will be the result of this query?

UPDATE employees SET salary = salary + 1000, bonus = 500 WHERE department = 'Sales';

medium

A. All employees get salary and bonus updated regardless of department.

B. Only the salary of Sales employees increases; bonus remains unchanged.

C. All employees in Sales get their salary increased by 1000 and bonus set to 500.

D. Syntax error because multiple columns cannot be updated together.

Solution

1. Step 1: Understand the WHERE clause effect

   The WHERE clause limits updates to rows where department = 'Sales'.

2. Step 2: Analyze SET clause changes

   Salary increases by 1000 and bonus is set to 500 for those rows only.

3. Final Answer:

   All employees in Sales get their salary increased by 1000 and bonus set to 500. -> Option C

4. Quick Check:

   WHERE filters rows; SET updates all listed columns [OK]

Hint: WHERE limits rows; SET updates all columns listed [OK]

Common Mistakes:

• Ignoring WHERE and updating all rows
• Thinking bonus stays unchanged
• Believing multiple columns update causes error

4. Identify the error in this SQL statement:

UPDATE orders SET status = 'Shipped' stock = 0 WHERE order_id = 123;

medium

A. WHERE clause should come before SET clause.

B. Missing comma between column assignments in SET clause.

C. Incorrect table name used.

D. Quotes around 'Shipped' should be double quotes.

Solution

1. Step 1: Check SET clause syntax

   Multiple columns must be separated by commas in SET clause.

2. Step 2: Identify missing comma

   Between status = 'Shipped' and stock = 0, a comma is missing.

3. Final Answer:

   Missing comma between column assignments in SET clause. -> Option B

4. Quick Check:

   Separate columns with commas in SET [OK]

Hint: Put commas between each column=value pair [OK]

Common Mistakes:

• Omitting commas between columns
• Placing WHERE before SET
• Using wrong quotes for strings

5. You want to update the price and discount columns in the products table only for items where category is 'Electronics' and current stock is less than 10. Which query correctly does this?

hard

A. UPDATE products SET price = price * 0.9, discount = 10 WHERE category = 'Electronics' AND stock < 10;

B. UPDATE products SET price = price * 0.9, discount = 10 WHERE category = 'Electronics' OR stock < 10;

C. UPDATE products SET price = price * 0.9 discount = 10 WHERE category = 'Electronics' AND stock < 10;

D. UPDATE products SET price = price * 0.9, discount = 10 WHERE category = 'Electronics' AND stock > 10;

Solution

1. Step 1: Understand the condition requirements

   We want to update only rows where category is 'Electronics' AND stock is less than 10.

2. Step 2: Check each option's WHERE clause and syntax

   UPDATE products SET price = price * 0.9, discount = 10 WHERE category = 'Electronics' AND stock < 10; uses AND with correct conditions and proper syntax. UPDATE products SET price = price * 0.9, discount = 10 WHERE category = 'Electronics' OR stock < 10; uses OR, which updates more rows. UPDATE products SET price = price * 0.9 discount = 10 WHERE category = 'Electronics' AND stock < 10; misses a comma between assignments. UPDATE products SET price = price * 0.9, discount = 10 WHERE category = 'Electronics' AND stock > 10; uses stock > 10, which is incorrect.

3. Final Answer:

   UPDATE products SET price = price * 0.9, discount = 10 WHERE category = 'Electronics' AND stock < 10; -> Option A

4. Quick Check:

   Use AND for combined conditions and commas between columns [OK]

Hint: Use AND for all conditions; separate columns with commas [OK]

Common Mistakes:

• Using OR instead of AND in WHERE
• Missing commas between columns
• Wrong comparison operators in WHERE