The most requested features and the versions in which they were implemented are summarized in the following table.
| Feature | MySQL Series |
|---|---|
| Unions | 4.0 |
| Subqueries | 4.1 |
| R-trees | 4.1 (for the MyISAM storage engine) |
| Stored procedures and functions | 5.0 |
| Views | 5.0 |
| Cursors | 5.0 |
| XA transactions | 5.0 |
| Triggers | 5.0 and 5.1 |
| Event scheduler | 5.1 |
| Partitioning | 5.1 |
| Pluggable storage engine API | 5.1 |
| Plugin API | 5.1 |
| InnoDB Plugin | 5.1 |
| Row-based replication | 5.1 |
| Server log tables | 5.1 |
| Scalability and performance improvements | 5.1 (with InnoDB Plugin) |
| DTrace support | 5.5 |
| InnoDB as default storage engine | 5.5 |
| Semisynchronous replication | 5.5 |
| SIGNAL/RESIGNAL support in stored routines | 5.5 |
| Performance Schema | 5.5 |
| Supplementary Unicode characters | 5.5 |
