Bug #4990 Functional Indexes

• Submitted: 11 Aug 2004 14:14
• Modified: 23 Jun 2015 14:05
• Reporter: Federico Razzoli (OCA)
• Status: Won't fix
• Category: MySQL Server: General
• Severity: S4 (Feature request)
• OS: Any
• CPU Architecture: Any

[11 Aug 2004 14:14] Federico Razzoli

Description:
I hope you will implement functional indexes, like PostgreSql. For example:

CREATE INDEX myindex ON mytable (MONTH(date))

or

CREATE INDEX myindex ON mytable (LEFT(REVERSE(textfield), 5))

or even:

CREATE INDEX myindex ON mytable ( CONCAT(IF(name IS NOT NULL, name, ''), ' ', surname) )

I think it would speed up seriously some searches...

How to repeat:
n/a

Suggested fix:
n/a

[2 Sep 2007 18:50] Valeriy Kravchuk

Thank you for a reasonable feature request.

[5 Oct 2008 11:58] Konstantin Osipov

Bug#24772 Function Based Indexes was marked a duplicate of this bug.

[10 Oct 2008 11:48] Alexander Barkov

Bug#17496 Function-based keys - was marked a duplicate for this report.

[25 Nov 2008 12:08] [ name withheld ]

Should be marked as duplicate of http://bugs.mysql.com/bug.php?id=14818

[25 Nov 2008 13:17] Valeriy Kravchuk

Bug #14818 was marked as a duplicate of this one.

[24 Aug 2009 8:12] Mattias Jonsson

Closed bug#36794 as a duplicate of this.

Also there is a community preview of Virtual Columns and functional indexes:
http://forge.mysql.com/wiki/MySQL_virtual_columns_preview

[1 Nov 2012 15:14] Bogdan Gusiev

Any progress on this?

[4 May 2015 18:59] Morgan Tocker

WL #411 was implemented in MySQL 5.7 (Generated columns).  The syntax is a little different from a purely functional index, but it should be feature equivalent.

[23 Jun 2015 14:04] Morgan Tocker

Posted by developer:
 
I am closing this bug now, as generated columns (WL#411) provides a suitable alternative to functional indexes.

If you believe this to be in error, please feel free to re-open this feature request.  We would value any input that demonstrates a clear use case where generated columns are not suitable, but functional indexes are. Thanks!