SQL SELECT INTO Statement

Understanding the SQL SELECT INTO Statement

Introduction:

The SQL SELECT INTO statement is used to create a new table and populate it with the result set of a SELECT query. It allows you to extract data from one or more existing tables and store it in a new table for further analysis or manipulation. The SELECT INTO statement is particularly useful when you want to create a temporary or backup table based on the data retrieved from other tables. In this article, we will explore the usage and examples of the SQL SELECT INTO statement to help you understand its functionality effectively.

Syntax:

The general syntax for the SQL SELECT INTO statement is as follows:

        SELECT column1, column2, ...
        INTO new_table
        FROM table_name
        WHERE condition;
    

Usage and Examples:

Let's consider a scenario where you have a table named "employees" with columns like "employee_id," "first_name," and "last_name." You want to create a new table named "employees_backup" and store the records of employees whose last name starts with 'S.' You can use the SQL SELECT INTO statement to accomplish this:

        SELECT *
        INTO employees_backup
        FROM employees
        WHERE last_name LIKE 'S%';
    

The above query will create a new table named "employees_backup" and populate it with the records from the "employees" table where the last name starts with 'S.' This allows you to have a separate backup table for the specified subset of data.

The SQL SELECT INTO statement can also be used to create a temporary table to perform further operations on the result set. For example, suppose you want to calculate the total salary of all employees in the "employees" table and store it in a temporary table for further analysis. Here's an example of using the SQL SELECT INTO statement with an aggregate function:

        SELECT SUM(salary) INTO total_salary
        FROM employees;
    

The above query will create a temporary table named "total_salary" and store the sum of all employee salaries from the "employees" table. You can then use this temporary table to perform further calculations or join it with other tables as needed.

Conclusion:

The SQL SELECT INTO statement is a powerful feature that allows you to create new tables and populate them with the result set of a SELECT query. It provides flexibility in managing and manipulating data by enabling you to extract specific subsets or perform calculations on the fly. Whether you need to create backup tables, store temporary data, or perform complex analyses, the SQL SELECT INTO statement is a valuable tool in your SQL arsenal. By mastering its usage and understanding its benefits, you can efficiently handle data extraction and transformation tasks in your database applications.