INSERT with SELECT in MySQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to insert all rows from old_table into new_table.

MySQL

INSERT INTO new_table SELECT * FROM [1];

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

Abackup_table

Bold_table

Ctemp_table

Dnew_table

Attempts:

3 left

💡 Hint

Common Mistakes

Using the target table name after FROM instead of the source table.

Confusing the order of tables in the statement.

The INSERT INTO ... SELECT statement copies rows from the source table (old_table) into the target table (new_table).

2fill in blank

medium

Complete the code to insert only the id and name columns from employees into staff.

MySQL

INSERT INTO staff (id, name) SELECT [1] FROM employees;

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

Aid, salary

Bname, salary

Cid, name

Did, department

Attempts:

3 left

💡 Hint

Common Mistakes

Selecting columns not listed in the INSERT clause.

Mixing up column order between INSERT and SELECT.

You must select the same columns in the same order as the columns listed in the INSERT statement.

3fill in blank

hard

Fix the error in the code to insert data from orders into archive_orders where status is 'completed'.

MySQL

INSERT INTO archive_orders SELECT * FROM orders WHERE status [1] 'completed';

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

A=

B==

CLIKE

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using == instead of =.

Using LIKE without wildcards.

In SQL, the equality operator is a single equals sign =, not double equals.

4fill in blank

hard

Fill both blanks to insert product_id and quantity from sales where quantity is greater than 10.

MySQL

INSERT INTO big_sales (product_id, quantity) SELECT product_id, quantity FROM sales WHERE quantity [1] [2];

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

A>

B<

C10

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Using < instead of >.

Using wrong number in the condition.

The condition must check if quantity is greater than 10, so use > 10.

5fill in blank

hard

Fill all three blanks to insert uppercase category and price from products where price is less than 100.

MySQL

INSERT INTO cheap_products (category, price) SELECT [1], [2] FROM products WHERE price [3] 100;

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

AUPPER(category)

Bprice

C<

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Not using UPPER() for category.

Using > instead of < for price condition.

Use UPPER(category) to convert category to uppercase, select price as is, and filter where price is less than 100.

Practice

1. What does the INSERT INTO ... SELECT statement do in MySQL?

easy

A. Copies rows from one table to another matching column structure

B. Deletes rows from a table based on a condition

C. Updates existing rows in a table

D. Creates a new table with selected columns

Solution

1. Step 1: Understand the purpose of INSERT INTO ... SELECT

   This statement copies data from one table to another by selecting rows from the source table.

2. Step 2: Recognize the matching column requirement

   The columns selected must match the target table's columns in number and type to insert correctly.

3. Final Answer:

   Copies rows from one table to another matching column structure -> Option A

4. Quick Check:

   INSERT with SELECT copies rows [OK]

Hint: Think of copying rows from one table to another [OK]

Common Mistakes:

• Confusing INSERT with SELECT as a delete or update operation
• Thinking it creates a new table
• Assuming it modifies existing rows instead of inserting

2. Which of the following is the correct syntax to insert rows from table1 into table2 using INSERT INTO ... SELECT?

easy

A. INSERT INTO table1 SELECT * FROM table2;

B. INSERT table2 INTO SELECT * FROM table1;

C. INSERT INTO table2 SELECT * FROM table1;

D. SELECT * INTO table2 FROM table1;

Solution

1. Step 1: Identify correct INSERT INTO ... SELECT syntax

   The correct syntax is INSERT INTO target_table SELECT ... FROM source_table;.

2. Step 2: Match the option to syntax

   INSERT INTO table2 SELECT * FROM table1; matches this syntax exactly, inserting rows from table1 into table2.

3. Final Answer:

   INSERT INTO table2 SELECT * FROM table1; -> Option C

4. Quick Check:

   Correct INSERT INTO ... SELECT syntax = INSERT INTO table2 SELECT * FROM table1; [OK]

Hint: Remember: INSERT INTO target SELECT ... FROM source [OK]

Common Mistakes:

• Swapping table names in INSERT and SELECT
• Using SELECT INTO which is not standard in MySQL
• Incorrect keyword order like INSERT table INTO

3. Given two tables:
employees(id, name, department)
managers(id, name, department)
What will be the result of this query?

INSERT INTO managers (id, name, department) SELECT id, name, department FROM employees WHERE department = 'Sales';

medium

A. Only employees from Sales department are copied to managers

B. All employees are copied to managers

C. No rows are copied because of syntax error

D. Only managers from Sales department are updated

Solution

1. Step 1: Analyze the SELECT part with WHERE clause

   The SELECT picks only employees where department equals 'Sales'.

2. Step 2: Understand INSERT INTO effect

   These selected rows are inserted into the managers table, adding only Sales department employees.

3. Final Answer:

   Only employees from Sales department are copied to managers -> Option A

4. Quick Check:

   WHERE filters rows inserted [OK]

Hint: WHERE filters rows to insert [OK]

Common Mistakes:

• Assuming all employees are copied ignoring WHERE
• Thinking it updates existing rows instead of inserting
• Confusing syntax causing no rows inserted

4. What is wrong with this query?

INSERT INTO products (id, name) SELECT id, name, price FROM items;

medium

A. Missing WHERE clause causes syntax error

B. Number of columns in INSERT and SELECT do not match

C. Table names are reversed

D. No error, query runs fine

Solution

1. Step 1: Compare columns in INSERT and SELECT

   INSERT specifies 2 columns (id, name), but SELECT returns 3 columns (id, name, price).

2. Step 2: Understand column count requirement

   Number of columns must match exactly; mismatch causes error.

3. Final Answer:

   Number of columns in INSERT and SELECT do not match -> Option B

4. Quick Check:

   Column count mismatch causes error [OK]

Hint: Match column count in INSERT and SELECT [OK]

Common Mistakes:

• Ignoring extra columns in SELECT
• Thinking WHERE is mandatory
• Assuming reversed table names cause error

5. You want to copy only unique customer emails from orders to newsletter_subscribers without duplicates. Which query achieves this?

hard

A. INSERT INTO newsletter_subscribers (email) SELECT email FROM orders GROUP BY email HAVING COUNT(*) > 1;

B. INSERT INTO newsletter_subscribers (email) SELECT email FROM orders WHERE email NOT IN newsletter_subscribers;

C. INSERT INTO newsletter_subscribers (email) SELECT email FROM orders WHERE email IS NULL;

D. INSERT INTO newsletter_subscribers (email) SELECT DISTINCT email FROM orders;

Solution

1. Step 1: Identify how to select unique emails

   Using SELECT DISTINCT email returns unique emails from orders.

2. Step 2: Insert unique emails into newsletter_subscribers

   INSERT INTO with SELECT DISTINCT copies only unique emails, avoiding duplicates.

3. Final Answer:

   INSERT INTO newsletter_subscribers (email) SELECT DISTINCT email FROM orders; -> Option D

4. Quick Check:

   Use DISTINCT to avoid duplicates [OK]

Hint: Use SELECT DISTINCT to insert unique rows [OK]

Common Mistakes:

• Using WHERE NOT IN with incorrect syntax
• Grouping but selecting only duplicates
• Inserting NULL emails unintentionally