INSERT INTO single row in SQL

Introduction

We use INSERT INTO to add new information (a single row) into a table in a database.

Adding a new customer record to a customer list.

Saving a new product in an online store's inventory.

Recording a new employee's details in the company database.

Entering a new book into a library catalog.

Logging a new order placed by a user.

Syntax

SQL

INSERT INTO table_name (column1, column2, column3) VALUES (value1, value2, value3);

The table_name is where you want to add the data.

You list the columns and then provide matching values in the same order.

Examples

Adds one employee named Alice, age 30, working in HR.

SQL

INSERT INTO employees (name, age, department) VALUES ('Alice', 30, 'HR');

Adds a product called Notebook priced at 2.5.

SQL

INSERT INTO products (product_name, price) VALUES ('Notebook', 2.5);

Adds a customer with ID 101 and name John Doe.

SQL

INSERT INTO customers (id, name) VALUES (101, 'John Doe');

Sample Program

This creates a table called students, inserts one student named Emma with grade A, then shows all students.

SQL

CREATE TABLE students (id INT, name VARCHAR(50), grade CHAR(1));
INSERT INTO students (id, name, grade) VALUES (1, 'Emma', 'A');
SELECT * FROM students;

Important Notes

If you skip columns, you must provide values for all columns that do not allow NULL.

Text values must be in single quotes.

Always check the order of columns and values to avoid mistakes.

Summary

INSERT INTO single row adds one new record to a table.

Specify the table, columns, and matching values.

Use single quotes for text and match the order carefully.

Practice

1. What does the SQL statement INSERT INTO students (name, age) VALUES ('Alice', 20); do?

easy

A. Deletes the student named Alice from the students table.

B. Adds a new student named Alice aged 20 to the students table.

C. Updates the age of all students to 20.

D. Creates a new table named students with columns name and age.

Solution

1. Step 1: Understand the INSERT INTO statement

   The statement adds data to an existing table by specifying columns and values.

2. Step 2: Match columns and values

   The columns are name and age, and the values are 'Alice' and 20, so a new row is added with these values.

3. Final Answer:

   Adds a new student named Alice aged 20 to the students table. -> Option B

4. Quick Check:

   INSERT INTO adds one row [OK]

Hint: INSERT INTO adds one row with matching columns and values [OK]

Common Mistakes:

• Confusing INSERT with DELETE or UPDATE
• Not matching columns and values order
• Using wrong quotes for text values

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

easy

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

B. INSERT INTO employees (id, name) SET (1, 'John');

C. INSERT INTO employees VALUES id=1, name='John';

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

Solution

1. Step 1: Recall correct INSERT syntax

   The correct syntax requires the keywords INSERT INTO, table name, columns in parentheses, then VALUES with matching values.

2. Step 2: Check each option

   INSERT INTO employees (id, name) VALUES (1, 'John'); matches the correct syntax exactly; others have missing INTO, wrong assignment, or SET keyword which is invalid here.

3. Final Answer:

   INSERT INTO employees (id, name) VALUES (1, 'John'); -> Option D

4. Quick Check:

   INSERT INTO ... VALUES (...) is correct syntax [OK]

Hint: Always use INSERT INTO table (columns) VALUES (values) [OK]

Common Mistakes:

• Omitting INTO keyword
• Using SET instead of VALUES
• Incorrect assignment inside VALUES

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

INSERT INTO products (product_id, product_name) VALUES (101, 'Pen');

medium

A. A new row with product_id 101 and product_name 'Pen' is added to products.

B. The query returns an error because product_name is text and needs double quotes.

C. The query updates product_id 101 to have product_name 'Pen'.

D. No change happens because INSERT INTO requires multiple rows.

Solution

1. Step 1: Understand the INSERT INTO effect

   The query adds one new row with specified values to the products table.

2. Step 2: Check syntax and data types

   Text values use single quotes in SQL, so 'Pen' is correct. No error occurs.

3. Final Answer:

   A new row with product_id 101 and product_name 'Pen' is added to products. -> Option A

4. Quick Check:

   INSERT INTO adds one row with given values [OK]

Hint: Text values need single quotes; INSERT adds one row [OK]

Common Mistakes:

• Using double quotes for text values
• Thinking INSERT updates existing rows
• Believing INSERT requires multiple rows

4. Identify the error in this SQL statement:

INSERT INTO orders (order_id, customer) VALUES (123, John);

medium

A. The table name orders is invalid.

B. Missing parentheses around the VALUES keyword.

C. Missing single quotes around the text value John.

D. Using double quotes instead of single quotes for John.

Solution

1. Step 1: Check the VALUES clause

   The value John is a text string and must be enclosed in single quotes in SQL.

2. Step 2: Verify other syntax parts

   Parentheses around VALUES are correct; table name orders is valid; double quotes are not used here.

3. Final Answer:

   Missing single quotes around the text value John. -> Option C

4. Quick Check:

   Text values need single quotes [OK]

Hint: Text values must be in single quotes [OK]

Common Mistakes:

• Forgetting quotes around text
• Using double quotes instead of single
• Misplacing parentheses

5. You have a table users with columns id (integer), username (text), and email (text). Which SQL statement correctly inserts a new user with id 5, username 'maria', and email '[e-mail]'?

hard

A. INSERT INTO users (id, username, email) VALUES (5, 'maria', '[e-mail]');

B. INSERT INTO users VALUES (5, maria, [e-mail]);

C. INSERT INTO users (id, username, email) VALUES ('5', 'maria', [e-mail]);

D. INSERT INTO users (id, username, email) SET (5, 'maria', '[e-mail]');

Solution

1. Step 1: Match columns and values correctly

   The columns id, username, and email are listed, so values must be in the same order and properly quoted.

2. Step 2: Check value types and syntax

   Integer 5 does not need quotes, text values 'maria' and '[e-mail]' need single quotes. INSERT INTO users (id, username, email) VALUES (5, 'maria', '[e-mail]'); matches this exactly.

3. Final Answer:

   INSERT INTO users (id, username, email) VALUES (5, 'maria', '[e-mail]'); -> Option A

4. Quick Check:

   Match columns and values with correct quotes [OK]

Hint: Match columns and values; quote text, not numbers [OK]

Common Mistakes:

• Not quoting text values
• Using SET instead of VALUES
• Quoting integers unnecessarily