SQL INSERT INTO Statement: A Comprehensive Guide with Examples

Introduction

In the world of databases, the SQL INSERT INTO statement plays a crucial role in adding new data records to a table. It allows you to insert one or more rows of data into a specific table, making it a fundamental command for data manipulation. In this article, we will explore the SQL INSERT INTO statement in detail, provide examples, and discuss its syntax and usage. So let’s dive in!

Table of Contents

  1. What is the INSERT INTO Statement in SQL?
  2. How to Insert Data into Variables in SQL?
  3. Generating INSERT Statements from SQL
  4. Using the WITH Clause in INSERT INTO Statements
  5. The Syntax of INSERT INTO in MySQL
  6. Conclusion
  7. FAQs

What is the INSERT INTO Statement in SQL?

The SQL INSERT INTO statement is used to insert new rows of data into a specified table. It allows you to add data into specific columns or all columns of a table, depending on your requirements. The basic syntax of the INSERT INTO statement is as follows:

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

Let’s consider an example to better understand how it works.

Example:

Suppose we have a table named customers with the following columns: customer_id, first_name, last_name, and email. To insert a new customer into the table, we can use the INSERT INTO statement like this:

INSERT INTO customers (first_name, last_name, email)
VALUES ('John', 'Doe', '[email protected]');

In this example, we specified the columns first_name, last_name, and email in the INSERT INTO statement and provided corresponding values for each column using the VALUES clause.

How to Insert Data into Variables in SQL?

In SQL, you can also insert data into variables and then use those variables to insert values into a table. This can be particularly useful when you want to manipulate or transform the data before inserting it. Here’s an example:

Example:

DECLARE @first_name VARCHAR(50) = 'Jane';
DECLARE @last_name VARCHAR(50) = 'Smith';
DECLARE @email VARCHAR(100) = '[email protected]';

INSERT INTO customers (first_name, last_name, email)
VALUES (@first_name, @last_name, @email);

In this example, we declared variables @first_name, @last_name, and @email with their respective values. Then, we used those variables in the INSERT INTO statement to insert the data into the customers table.

Generating INSERT Statements from SQL

Sometimes, you may need to generate INSERT statements based on existing data in your database. This can be helpful when you

want to replicate or export data from one table to another. One way to accomplish this is by using the SELECT statement within the INSERT INTO statement. Let’s see an example:

Example:

Suppose we have a table named employees with columns employee_id, first_name, last_name, and salary. To generate INSERT statements for all employees with a salary greater than $50,000, we can use the following query:

INSERT INTO new_employees (employee_id, first_name, last_name, salary)
SELECT employee_id, first_name, last_name, salary
FROM employees
WHERE salary > 50000;

In this example, we used the SELECT statement to retrieve the data from the employees table based on the condition salary > 50000, and then we inserted that data into the new_employees table.

Using the WITH Clause in INSERT INTO Statements

The SQL INSERT INTO statement also allows you to use the WITH clause, which is used for creating temporary result sets within a query. This can be handy when you want to insert data into a table while performing additional operations on the inserted data. Here’s an example:

Example:

WITH new_customer AS (
  SELECT 'Jane' AS first_name, 'Doe' AS last_name, '[email protected]' AS email
)
INSERT INTO customers (first_name, last_name, email)
SELECT first_name, last_name, email
FROM new_customer;

In this example, we used the WITH clause to create a temporary result set called new_customer with specific values for first_name, last_name, and email. Then, we inserted the data from new_customer into the customers table using the SELECT statement.

The Syntax of INSERT INTO in MySQL

When working with MySQL, the syntax of the INSERT INTO statement is slightly different. Here’s the general format:

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

Example:

Suppose we have a table named products with columns product_id, name, price, and quantity. To insert a new product into the table, we can use the following syntax:

INSERT INTO products
SET name = 'iPhone', price = 999, quantity = 10;

In this example, we used the SET keyword to assign values to the columns name, price, and quantity directly in the INSERT INTO statement.

Conclusion

In this article, we covered the SQL INSERT INTO statement and its various aspects. We discussed its purpose, syntax, and usage with examples. The INSERT INTO statement is a powerful tool for adding new data into database tables, and understanding its usage is essential for effective data manipulation. So go ahead, use the knowledge you’ve gained to incorporate the INSERT INTO statement into your SQL queries and enhance your database management skills.


FAQs

  1. What is the insert into statement in SQL?
    The SQL INSERT INTO statement is used to add new rows of data into a specific table in a database.
  2. How to insert data into variables in SQL?
    In SQL, you can insert data into variables and then use those variables to insert values into a table. This allows for data manipulation before insertion.
  3. How to generate insert statements from SQL?
    To generate INSERT statements from existing data in SQL, you can use the SELECT statement within the INSERT INTO statement.
  4. Can we use WITH in insert into SQL?
    Yes, you can use the WITH clause in the INSERT INTO statement to create temporary result sets and perform additional operations on the inserted data.
  5. What is the syntax of insert into in MySQL?
    In MySQL, the syntax of the INSERT INTO statement is slightly different. Instead of using the VALUES keyword, you can use the SET keyword to assign values to columns directly in the INSERT INTO statement.

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