Introduction to Global Temporary Tables in MySQL

Global temporary tables are a valuable feature in MySQL that allow you to create temporary storage for data that is session-specific and shared across multiple SQL statements. These tables are useful for various tasks, such as intermediate data storage and complex data manipulations. In this guide, we'll explore how to create and use global temporary tables effectively in MySQL.

Key Characteristics of Global Temporary Tables

Global temporary tables in MySQL have several important characteristics:

• They are session-specific, meaning they exist only for the duration of the database session.
• They can be accessed by multiple SQL statements within the same session.
• Data in global temporary tables is automatically deleted at the end of the session or when the table is explicitly dropped.

Creating Global Temporary Tables

The syntax for creating global temporary tables in MySQL is as follows:

            CREATE TEMPORARY TABLE table_name (
                column1 datatype,
                column2 datatype,
                -- Define columns and their data types
            );
        

The keyword "TEMPORARY" indicates that it's a temporary table.

Examples of Using Global Temporary Tables

Let's consider some examples to understand how to create and use global temporary tables in MySQL:

            -- Example 1: Create a global temporary table to store intermediate results
            CREATE TEMPORARY TABLE temp_sales_data (
                order_id INT,
                total_amount DECIMAL(10, 2)
            );
        

            -- Example 2: Insert data into the temporary table
            INSERT INTO temp_sales_data (order_id, total_amount)
            SELECT order_id, SUM(amount) FROM orders GROUP BY order_id;
        

Manipulating and Dropping Global Temporary Tables

You can perform various operations on global temporary tables, such as SELECT, INSERT, UPDATE, DELETE, and DROP. The table and its data will be automatically removed when the session ends, or you can explicitly drop it using:

            DROP TEMPORARY TABLE table_name;
        

Conclusion

Global temporary tables in MySQL are a versatile tool for temporary data storage and complex data transformations within a session. By understanding how to create, use, and manage these tables, you can improve the efficiency and flexibility of your database operations.