Bug #30475 EXPLAIN docs don't show all zero_result_cause messages
Submitted: 17 Aug 2007 14:32 Modified: 22 Mar 2010 15:47
Reporter: Baron Schwartz (Basic Quality Contributor) Email Updates:
Status: Closed Impact on me:
None 
Category:MySQL Server: Documentation Severity:S3 (Non-critical)
Version: OS:Any
Assigned to: Paul DuBois CPU Architecture:Any

[17 Aug 2007 14:32] Baron Schwartz 
Description:
The EXPLAIN documentation doesn't mention the following items that may appear in the Extra field due to the zero_result_cause variable being set to them:

Impossible HAVING
Impossible WHERE
No matching min/max row
no matching row in const table

It does mention "Impossible WHERE noticed after reading const tables" but "Impossible WHERE" appears separately in the source code and I'm not sure it means the same thing.

How to repeat:
Doc bug
[17 Aug 2007 14:50] Baron Schwartz 
I'm also noticing that tab->info can be set to

const row not found
unique row not found

And these values are also appended to the Extra output, but not documented.
[17 Aug 2007 19:01] Valeriy Kravchuk 
Thank you for a reasonable documentation request.
[22 Mar 2010 15:47] Paul DuBois 
Thank you for your bug report. This issue has been addressed in the documentation. The updated documentation will appear on our website shortly, and will be included in the next release of the relevant products.

Updated http://dev.mysql.com/doc/refman/5.1/en/using-explain.html