MySQL Bugs: #88450: Multiple DISTINCTs are allowed

Bug #88450	Multiple DISTINCTs are allowed
Submitted:	12 Nov 2017 11:09	Modified:	12 Nov 2017 13:28
Reporter:	Federico Razzoli (OCA)	Email Updates:
Status:	Verified	Impact on me:	None
Category:	MySQL Server: Parser	Severity:	S3 (Non-critical)
Version:	5.5/5.6/5.7/8.0	OS:	Any
Assigned to:		CPU Architecture:	Any

View
Add Comment
Files
Developer
Edit Submission
View Progress Log
Contributions

Description:
These queries work, which seems to me inconsistent:

SELECT DISTINCT DISTINCT DISTINCTROW DISTINCTROW SCHEMA_NAME FROM information_schema.SCHEMATA;

SELECT ALL ALL SCHEMA_NAME FROM information_schema.SCHEMATA;

Fortunately, a combination of ALL + DISTINCT[ROW] doesn't work. However, such a query is clearly the result of an application bug (which probably means, the developer has no idea what the ORM does), and it would be useful to reject it.

I think this affects all MySQL versions until now.

How to repeat:
.

Suggested fix:
Deprecate this syntax and remove it in a future version.

Thank you for the bug report.