MySQL Bugs: #88591: When no default dataabse incorrect error occurs

Bug #88591	When no default dataabse incorrect error occurs
Submitted:	21 Nov 2017 12:26	Modified:	21 Mar 2018 5:55
Reporter:	Peter Laursen (Basic Quality Contributor)	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Errors	Severity:	S3 (Non-critical)
Version:	8.03	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
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Server version: 8.0.3-rc-log MySQL Community Server (GPL)

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mysql> explain extended select 1;
ERROR 1046 (3D000): No database selected
mysql> use mysql;
Database changed
mysql> explain extended select 1;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'select 1' at line 1
mysql>

How to repeat:
See above. Also note that in pre-8 server versions a default database is not required to execute the statement. And on 8.x a plain EXPLAIN it also still is not.

Suggested fix:
Error 1064 should be returned in both cases, as EXPLAIN EXTENDED is no longer supported (with or without an active database context).

Thank you for the bug report. Verified as described.

Documented fix in the MySQL 8.0.11 changelog as follows:

    When executed prior to selecting a database, EXPLAIN EXTENDED
    raised Error 1046 No database selected instead of an SQL syntax
    error due to the fact that the EXTENDED keyword has been
    removed.

Closed.