如何在 MySQL 中启用严格的 sql_mode？

Question

How can I enable strict sql_mode in MySQL?

I want to fetch data from SQL and process the same in strict mode.

My current sql_mode is:

mysql> SELECT @@sql_mode;
+------------------------+
| @@sql_mode             |
+------------------------+
| NO_ENGINE_SUBSTITUTION |
+------------------------+

Answer 1

执行以下操作：

SET GLOBAL sql_mode='STRICT_TRANS_TABLES';

Answer 2

You basically have two ways of doing it, using SQL command or changing configuration file. If you set it using SQL command - it will change back after the server is restarted.

Doing it in SQL:

SET GLOBAL sql_mode='STRICT_TRANS_TABLES';

Doing it in config file:

[mysqld] sql_mode="STRICT_TRANS_TABLES"

File location varies depending on your operating system, more on where to find it here: https://dev.mysql.com/doc/refman/5.7/en/option-files.html

Important to note, that you can have multiple modes specified:

sql_mode="STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION"

this is especially important when using SQL statement, since it could override your whole mode string.

More stuff about SQL modes here: https://dev.mysql.com/doc/refman/5.7/en/sql-mode.html

Answer 3

The other answers are correct, but they don't work (as-is) for AWS RDS.

If you are running a MySQL server on AWS RDS, then you can't run SET GLOBAL sql_mode='STRICT_TRANS_TABLES'; straightaway because you don't have the requisite permissions, even with admin-level credentials:

mysql> SET GLOBAL sql_mode='STRICT_ALL_TABLES';
ERROR 1227 (42000): Access denied; you need (at least one of) the SUPER or SYSTEM_VARIABLES_ADMIN privilege(s) for this operation

In AWS RDS, since it's a managed DB service, you don't have access to the my.cnf or other configuration files directly - so you can't change the settings there either.

However, note that you can set sql_mode at the session-level, but this will be lost across session changes or reboots:

mysql> SET SESSION  sql_mode='STRICT_ALL_TABLES';
Query OK, 0 rows affected, 1 warning (0.30 sec)

mysql> SELECT @@session.sql_mode;
+---------------------+
| @@session.sql_mode  |
+---------------------+
| STRICT_ALL_TABLES   |
+---------------------+
1 row in set (0.31 sec)

So then how do you change sql_mode (or any other parameters for that matter) at a GLOBAL level so that they persist across restarts in AWS RDS MySQL?

You need to create a custom DB Parameter Group in RDS (for example, using the web console) like this:

Then you have to modify your RDS instance and apply the newly-created Parameter Group like so:

Finally, apply your modifications, and reboot (yes, reboot is required) the instance.

And voila, you have your sql_mode set as needed, and it persists across reboots now:

mysql> SELECT @@sql_mode;
+------------------------------------------+
| @@sql_mode                               |
+------------------------------------------+
| STRICT_ALL_TABLES,NO_ENGINE_SUBSTITUTION |
+------------------------------------------+
1 row in set (0.69 sec)


mysql> SELECT @@global.sql_mode;
+------------------------------------------+
| @@global.sql_mode                        |
+------------------------------------------+
| STRICT_ALL_TABLES,NO_ENGINE_SUBSTITUTION |
+------------------------------------------+
1 row in set (0.62 sec)


mysql> SELECT @@session.sql_mode;
+------------------------------------------+
| @@session.sql_mode                       |
+------------------------------------------+
| STRICT_ALL_TABLES,NO_ENGINE_SUBSTITUTION |
+------------------------------------------+
1 row in set (0.38 sec)