Why INSERT matters in SQL - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to insert a new row into the table.

SQL

INSERT INTO employees (name, age) VALUES ([1], 30);

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

Aage

BJohn

C'John'

D30

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to use quotes around string values.

Using a number instead of a string for the name.

The value for the name must be a string enclosed in single quotes.

2fill in blank

medium

Complete the code to insert a row with all columns specified.

SQL

INSERT INTO products (id, name, price) VALUES ([1], 'Book', 9.99);

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

Aprice

B'001'

CBook

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Putting numbers inside quotes when not needed.

Using the wrong data type for the id.

The id is usually a number without quotes, so 1 is correct.

3fill in blank

hard

Fix the error in the INSERT statement by completing the missing keyword.

SQL

INSERT [1] customers (name, email) VALUES ('Alice', '[e-mail]');

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

AFROM

BINTO

CVALUES

DSET

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting INTO keyword.

Using FROM instead of INTO.

The correct syntax is INSERT INTO table_name ...

4fill in blank

hard

Fill both blanks to insert a new record with specified columns and values.

SQL

INSERT [1] orders (order_id, customer) [2] (101, 'Bob');

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

AINTO

BVALUES

CSET

DFROM

Attempts:

3 left

💡 Hint

Common Mistakes

Using SET instead of VALUES.

Omitting INTO keyword.

Use INSERT INTO to specify the table and VALUES to provide the data.

5fill in blank

hard

Fill in the blanks to insert multiple rows in one statement.

SQL

INSERT [1] customers (name, age) [2] ('Eve', 28), ('Sam', 35);

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

AINTO

BVALUES

DFROM

Attempts:

3 left

💡 Hint

Common Mistakes

Using FROM instead of INTO.

Missing VALUES keyword before data.

Trying to use multiple VALUES keywords.

Use INSERT INTO to specify the table, then VALUES followed by multiple sets of data separated by commas.

Practice

1. What is the main purpose of the INSERT statement in SQL?

easy

A. To add new rows of data into a table

B. To delete rows from a table

C. To update existing data in a table

D. To create a new table

Solution

1. Step 1: Understand the role of INSERT

   The INSERT statement is used to add new data rows into an existing table.

2. Step 2: Compare with other SQL commands

   DELETE removes rows, UPDATE changes existing data, and CREATE makes new tables, so these are different from INSERT.

3. Final Answer:

   To add new rows of data into a table -> Option A

4. Quick Check:

   INSERT adds rows = D [OK]

Hint: INSERT always adds new rows, not changes or deletes [OK]

Common Mistakes:

• Confusing INSERT with UPDATE or DELETE
• Thinking INSERT creates tables
• Assuming INSERT modifies existing rows

2. Which of the following is the correct syntax to insert a new row into a table named users with columns id and name?

easy

A. INSERT INTO users VALUES id=1, name='Alice';

B. INSERT users INTO (id, name) VALUES (1, 'Alice');

C. INSERT INTO users (id, name) VALUES (1, 'Alice');

D. INSERT (id, name) INTO users VALUES (1, 'Alice');

Solution

1. Step 1: Recall correct INSERT syntax

   The correct syntax is: INSERT INTO table_name (columns) VALUES (values);

2. Step 2: Check each option

   INSERT INTO users (id, name) VALUES (1, 'Alice'); matches the correct syntax exactly. Options A, B, and D have incorrect order or missing keywords.

3. Final Answer:

   INSERT INTO users (id, name) VALUES (1, 'Alice'); -> Option C

4. Quick Check:

   Correct INSERT syntax = C [OK]

Hint: Remember: INSERT INTO table (cols) VALUES (vals); [OK]

Common Mistakes:

• Swapping INTO and table name
• Omitting INTO keyword
• Using assignment inside VALUES

3. Given the table products with columns product_id and product_name, what will be the result of this query?

INSERT INTO products (product_id, product_name) VALUES (101, 'Pen');
SELECT * FROM products WHERE product_id = 101;

medium

A. No rows returned

B. One row with product_id 101 and product_name 'Pen'

C. Syntax error in INSERT statement

D. Multiple rows with product_id 101

Solution

1. Step 1: Understand the INSERT effect

   The INSERT adds a new row with product_id 101 and product_name 'Pen' to the products table.

2. Step 2: Analyze the SELECT query

   The SELECT searches for rows with product_id 101, which now includes the newly inserted row.

3. Final Answer:

   One row with product_id 101 and product_name 'Pen' -> Option B

4. Quick Check:

   INSERT adds row, SELECT finds it = B [OK]

Hint: INSERT adds row, SELECT finds it immediately after [OK]

Common Mistakes:

• Assuming INSERT does not add data immediately
• Thinking SELECT returns no rows
• Confusing syntax errors with correct queries

4. What is wrong with this SQL statement?

INSERT INTO employees (id, name) VALUES 1, 'John';

medium

A. Missing parentheses around VALUES

B. Incorrect table name

C. Missing comma between columns

D. VALUES keyword is misspelled

Solution

1. Step 1: Check VALUES syntax

   The VALUES keyword must be followed by parentheses enclosing the values, like VALUES (1, 'John').

2. Step 2: Identify the error in the statement

   The statement lacks parentheses around the values, causing a syntax error.

3. Final Answer:

   Missing parentheses around VALUES -> Option A

4. Quick Check:

   VALUES needs parentheses = A [OK]

Hint: Always put values inside parentheses after VALUES [OK]

Common Mistakes:

• Omitting parentheses around values
• Confusing column list commas
• Misspelling keywords

5. You have a table orders with columns order_id, customer, and amount. You want to insert multiple new orders in one statement. Which SQL command correctly inserts two rows at once?

hard

A. INSERT INTO orders (order_id, customer, amount) VALUES (1, 'Anna', 100) OR (2, 'Ben', 150);

B. INSERT INTO orders VALUES (1, 'Anna', 100); INSERT INTO orders VALUES (2, 'Ben', 150);

C. INSERT INTO orders (order_id, customer, amount) VALUES (1, 'Anna', 100) AND (2, 'Ben', 150);

D. INSERT INTO orders (order_id, customer, amount) VALUES (1, 'Anna', 100), (2, 'Ben', 150);

Solution

1. Step 1: Understand multi-row INSERT syntax

   To insert multiple rows in one statement, list each row's values separated by commas inside VALUES.

2. Step 2: Evaluate each option

   INSERT INTO orders (order_id, customer, amount) VALUES (1, 'Anna', 100), (2, 'Ben', 150); correctly uses comma-separated tuples. INSERT INTO orders VALUES (1, 'Anna', 100); INSERT INTO orders VALUES (2, 'Ben', 150); uses two separate statements, which is valid but not one statement. Options C and D use invalid keywords AND/OR instead of commas.

3. Final Answer:

   INSERT INTO orders (order_id, customer, amount) VALUES (1, 'Anna', 100), (2, 'Ben', 150); -> Option D

4. Quick Check:

   Multiple rows use commas in VALUES = A [OK]

Hint: Use commas between value sets to insert multiple rows [OK]

Common Mistakes:

• Using AND/OR instead of commas between rows
• Writing multiple separate INSERT statements
• Omitting parentheses around each row