Skip to content

sql-mode: update compatibility (#3192) #3234

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
5 commits merged into from
Jul 10, 2020
Merged

sql-mode: update compatibility (#3192) #3234

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
ce8b270
cherry pick #3192 to release-3.0
Jul 10, 2020
f9b74ba
Update TOC.md
Jul 10, 2020
acdb574
Update assign-by-files.yml
Jul 10, 2020
4fca030
Delete assign-by-files.yml
Jul 10, 2020
e273d37
Update mysql-compatibility.md
Jul 10, 2020
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
10 changes: 5 additions & 5 deletions mysql-compatibility.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@ TiDB supports both the MySQL wire protocol and the majority of its syntax. This

Currently TiDB Server advertises itself as MySQL 5.7 and works with most MySQL database tools such as PHPMyAdmin, Navicat, MySQL Workbench, mysqldump, and Mydumper/myloader.

However, TiDB does not support some of MySQL features or behaves differently from MySQL because these features cannot be easily implemented in a distributed system. For some MySQL syntax, TiDB can parse but does not process it. For example, the `ENGINE` table option in the `CREATE TABLE` statement can be parsed but is ignored.
However, some features of MySQL are not supported. This could be because there is now a better way to solve the problem (such as XML functions superceded by JSON), or a lack of current demand versus effort required (such as stored procedures and functions). Some features might also be difficult to implement as a distributed system.

> **Note:**
>
Expand Down Expand Up @@ -187,11 +187,11 @@ Architecturally, TiDB does support a similar storage engine abstraction to MySQL

### SQL modes

TiDB supports **all of the SQL modes** from MySQL 5.7 with minor exceptions:
TiDB supports most [SQL modes](/sql-mode.md):

- The compatibility modes deprecated in MySQL 5.7 and removed in MySQL 8.0 are not supported (such as `ORACLE`, `POSTGRESQL` etc).
- The mode `ONLY_FULL_GROUP_BY` has minor [semantic differences](/functions-and-operators/aggregate-group-by-functions.md#differences-from-mysql) to MySQL 5.7, which we plan to address in the future.
- The SQL modes `NO_DIR_IN_CREATE` and `NO_ENGINE_SUBSTITUTION` are supported for compatibility, but are not applicable to TiDB.
- The compatibility modes, such as `ORACLE` and `POSTGRESQL` are parsed but ignored. Compatibility modes are deprecated in MySQL 5.7 and removed in MySQL 8.0.
- The `ONLY_FULL_GROUP_BY` mode has minor [semantic differences](/functions-and-operators/aggregate-group-by-functions.md#differences-from-mysql) from MySQL 5.7.
- The `NO_DIR_IN_CREATE` and `NO_ENGINE_SUBSTITUTION` SQL modes in MySQL are accepted for compatibility, but are not applicable to TiDB.

### Version-specific comments

Expand Down
16 changes: 8 additions & 8 deletions sql-mode.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -49,12 +49,12 @@ Ensure that you have `SUPER` privilege when setting SQL mode at `GLOBAL` level,
| `NO_ENGINE_SUBSTITUTION` | Prevents the automatic replacement of storage engines if the required storage engine is disabled or not compiled. (syntax support only)|
| `PAD_CHAR_TO_FULL_LENGTH` | If this mode is enabled, the system does not trim the trailing spaces for `CHAR` types. (full support) |
| `REAL_AS_FLOAT` | Treats `REAL` as the synonym of `FLOAT`, not the synonym of `DOUBLE` (full support)|
| `POSTGRESQL` | Equivalent to `PIPES_AS_CONCAT`, `ANSI_QUOTES`, `IGNORE_SPACE`, `NO_KEY_OPTIONS`, `NO_TABLE_OPTIONS`, `NO_FIELD_OPTIONS` (full support)|
| `MSSQL` | Equivalent to `PIPES_AS_CONCAT`, `ANSI_QUOTES`, `IGNORE_SPACE`, `NO_KEY_OPTIONS`, `NO_TABLE_OPTIONS`, `NO_FIELD_OPTIONS` (full support)|
| `DB2` | Equivalent to `PIPES_AS_CONCAT`, `ANSI_QUOTES`, `IGNORE_SPACE`, `NO_KEY_OPTIONS`, `NO_TABLE_OPTIONS`, `NO_FIELD_OPTIONS` (full support)|
| `POSTGRESQL` | Equivalent to `PIPES_AS_CONCAT`, `ANSI_QUOTES`, `IGNORE_SPACE`, `NO_KEY_OPTIONS`, `NO_TABLE_OPTIONS`, `NO_FIELD_OPTIONS` (syntax support only)|
| `MSSQL` | Equivalent to `PIPES_AS_CONCAT`, `ANSI_QUOTES`, `IGNORE_SPACE`, `NO_KEY_OPTIONS`, `NO_TABLE_OPTIONS`, `NO_FIELD_OPTIONS` (syntax support only)|
| `DB2` | Equivalent to `PIPES_AS_CONCAT`, `ANSI_QUOTES`, `IGNORE_SPACE`, `NO_KEY_OPTIONS`, `NO_TABLE_OPTIONS`, `NO_FIELD_OPTIONS` (syntax support only)|
| `MAXDB` | Equivalent to `PIPES_AS_CONCAT`, `ANSI_QUOTES`, `IGNORE_SPACE`, `NO_KEY_OPTIONS`, `NO_TABLE_OPTIONS`, `NO_FIELD_OPTIONS`, `NO_AUTO_CREATE_USER` (full support)|
| `MySQL323` | Equivalent to `NO_FIELD_OPTIONS`, `HIGH_NOT_PRECEDENCE` (full support)|
| `MYSQL40` | Equivalent to `NO_FIELD_OPTIONS`, `HIGH_NOT_PRECEDENCE` (full support)|
| `ANSI` | Equivalent to `REAL_AS_FLOAT`, `PIPES_AS_CONCAT`, `ANSI_QUOTES`, `IGNORE_SPACE` (full support)|
| `TRADITIONAL` | Equivalent to `STRICT_TRANS_TABLES`, `STRICT_ALL_TABLES`, `NO_ZERO_IN_DATE`, `NO_ZERO_DATE`, `ERROR_FOR_DIVISION_BY_ZERO`, `NO_AUTO_CREATE_USER` (full support) |
| `ORACLE` | Equivalent to `PIPES_AS_CONCAT`, `ANSI_QUOTES`, `IGNORE_SPACE`, `NO_KEY_OPTIONS`, `NO_TABLE_OPTIONS`, `NO_FIELD_OPTIONS`, `NO_AUTO_CREATE_USER` (full support)|
| `MySQL323` | Equivalent to `NO_FIELD_OPTIONS`, `HIGH_NOT_PRECEDENCE` (syntax support only)|
| `MYSQL40` | Equivalent to `NO_FIELD_OPTIONS`, `HIGH_NOT_PRECEDENCE` (syntax support only)|
| `ANSI` | Equivalent to `REAL_AS_FLOAT`, `PIPES_AS_CONCAT`, `ANSI_QUOTES`, `IGNORE_SPACE` (syntax support only)|
| `TRADITIONAL` | Equivalent to `STRICT_TRANS_TABLES`, `STRICT_ALL_TABLES`, `NO_ZERO_IN_DATE`, `NO_ZERO_DATE`, `ERROR_FOR_DIVISION_BY_ZERO`, `NO_AUTO_CREATE_USER` (syntax support only) |
| `ORACLE` | Equivalent to `PIPES_AS_CONCAT`, `ANSI_QUOTES`, `IGNORE_SPACE`, `NO_KEY_OPTIONS`, `NO_TABLE_OPTIONS`, `NO_FIELD_OPTIONS`, `NO_AUTO_CREATE_USER` (syntax support only)|