# Limitations of `MySQL` Syntax Support

__*Limitations of MySQL syntax support*__
__*MySQL syntax compatibility*__
__*zz-BGL*__

+ Features not supported:
  + Stored procedure
  + Trigger
  + Custom function
  + ...

-------------------------------------------------------------
Features not supported:
- Stored procedure
- Trigger
- Event
- Custom function
- `Full Text/Spatial` function and indexes
- Non `ascii/latin1/binary/utf8/utf8mb4` character sets
- `SYS` schema
- `MySQL trace` optimizer
- `XML` function
- `X-Protocol`
- Column level privilege
- `XA` syntax (`TiDB` uses a `2-phase commit` internally, but it is not exposed through the `SQL` interface)
- `CREATE TABLE ... AS SELECT` syntax
- `CHECK TABLE` syntax
- `CHECKSUM TABLE` syntax

For details, please refer to: `https://docs.pingcap.com/zh/tidb/stable/mysql-compatibility`.