How to use MySQL's temporary table for temporary data storage and processing

How to use MySQL's temporary table for temporary data storage and processing

Introduction:
MySQL is a popular relational database management system that is widely used in various applications. A temporary table is a special table provided by MySQL that can be used to temporarily store and process data. This article will introduce how to use MySQL's temporary table for temporary data storage and processing, and provide relevant code examples.

1. What is a temporary table
A temporary table is a special table in MySQL, and its existence is limited to the current session. When the session ends, the temporary table is automatically deleted. The structure of a temporary table is the same as an ordinary table, and data can be inserted, updated, and deleted in the temporary table. Temporary tables are ideal for scenarios where data needs to be temporarily stored and processed within a session.

2. Create a temporary table
You can use the CREATE TEMPORARY TABLE statement to create a temporary table. For example, create a temporary table named tmp_table, containing two columns: id and name:

CREATE TEMPORARY TABLE tmp_table (

id INT,
name VARCHAR(50)

);

3. To the temporary table Insert data
You can use the INSERT INTO statement to insert data into the temporary table. For example, insert a piece of data with id 1 and name "John Smith":

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

4. From Reading data from temporary tables
You can use the SELECT statement to read data from temporary tables. For example, query the record with id 1:

SELECT * FROM tmp_table WHERE id = 1;

5. Update the data of the temporary table
You can use the UPDATE statement to update the data of the temporary table. For example, change the name of the record named "John Smith" to "Jane Doe":

UPDATE tmp_table SET name = 'Jane Doe' WHERE name = 'John Smith';

Six , Delete the data of the temporary table
You can use the DELETE statement to delete the data of the temporary table. For example, delete the record with id 1:

DELETE FROM tmp_table WHERE id = 1;

7. The scope of the temporary table
The scope of the temporary table is limited to the current session. This means that the temporary table can only be accessed and used within the session in which it was created. Other sessions cannot access the temporary table.

8. Life cycle of temporary table
The life cycle of temporary table is related to the session. When the session ends, the temporary table will be automatically deleted to free up the occupied space. Temporary tables can be dropped explicitly using the DROP TEMPORARY TABLE statement.

DROP TEMPORARY TABLE tmp_table;

9. Performance optimization of temporary tables
In order to improve the performance of temporary tables, appropriate indexes and partitions can be set according to needs. In addition, query cache and in-memory tables can be used appropriately to speed up operations on temporary tables.

Conclusion:
Temporary table is a special table in MySQL, used for temporary storage and processing of data. This article describes how to create a temporary table, insert, read, and update data into a temporary table, as well as the scope and life cycle of a temporary table. Using temporary tables can simplify database design and data processing, and improve the efficiency of queries and operations.

Code example:

CREATE TEMPORARY TABLE tmp_table (

id INT,
name VARCHAR(50)

);

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

SELECT * FROM tmp_table WHERE id = 1;

UPDATE tmp_table SET name = 'Jane Doe' WHERE name = 'John Smith';

DELETE FROM tmp_table WHERE id = 1;

DROP TEMPORARY TABLE tmp_table;

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