Here’s a clear comparison between temporary tables and regular tables in MySQL:
| Feature | Temporary Table | Regular Table |
|---|---|---|
| Definition | A table that exists only for the duration of a session (or until explicitly dropped). | A normal table stored permanently in the database until dropped. |
| Lifetime | Automatically dropped when the session ends (or can be explicitly dropped). | Exists until explicitly dropped. |
| Scope | Only visible to the session that created it. Other sessions cannot access it. | Accessible by any session/user with appropriate privileges. |
| Data Storage | Stored in the tmp database internally (depends on storage engine, often in memory). | Stored in the database permanently using the chosen storage engine (InnoDB, MyISAM, etc.). |
| Indexing | Can have indexes like a regular table, but usually small and temporary. | Fully supports indexing, constraints, and foreign keys. |
| Constraints | Foreign keys are generally not allowed. | Supports all constraints including primary key, foreign key, unique, etc. |
| Use Case | Used for intermediate calculations, session-specific processing, temporary storage in complex queries. | Used to store persistent data of the application. |
| Creation Syntax | CREATE TEMPORARY TABLE temp_table_name (...); | CREATE TABLE table_name (...); |
| Collision | Multiple sessions can create temporary tables with the same name without conflict. | Table names must be unique within a database. |
Key Notes:
- Temporary tables are session-specific; if two users create a temporary table with the same name, they won’t interfere with each other.
- Regular tables are permanent and shared across sessions.