Bug #94316 JSON type can have default value of null in table creation

• Submitted: 13 Feb 2019 18:55
• Modified: 19 Feb 2019 15:58
• Reporter: Randen Kelly
• Status: Closed
• Category: MySQL Server: Data Types
• Severity: S3 (Non-critical)
• Version: 5.7+
• OS: Any
• CPU Architecture: Any

[13 Feb 2019 18:55] Randen Kelly

Description:
Documentation says "A JSON column cannot have a default value.". Yet this is possible when creating a table.

Although, Modifying a column does not allow you to do this.

How to repeat:
Create a table with a JSON type column with DEFAULT NULL.

CREATE TABLE `test` (
`foo` json DEFAULT NULL
);

Suggested fix:
Restrict this in table creation just as it is done in ALTER statments

[13 Feb 2019 20:19] MySQL Verification Team

Thank you for the bug report.

[19 Feb 2019 15:58] Paul DuBois

Posted by developer:
 
Corrections made:

https://dev.mysql.com/doc/refman/5.7/en/json.html

A JSON column cannot have a non-NULL default value.

https://dev.mysql.com/doc/refman/8.0/en/json.html

Prior to MySQL 8.0.13, a JSON column cannot have a non-NULL default value.