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Displaying posts with tag: ISO 9075 (reset)
MySQL 5.7.5: GROUP BY respects functional dependencies!

Today, Oracle announced the availability of the Development Milestone Release 15 of MySQL 5.7.5. The tagline for this release promises "Enhanced Database Performance and Manageability". That may sound rather generic, the actual list of changes and improvements is simply *huge*, and includes many items that I personally find rather exciting! Perhaps I'm mistaken but I think this may be one of the largest number of changes packed into a MySQL point release that I've witnessed in a long time. The list of changes includes improvements such as:

  • InnoDB improvements: Simplified tablespace recovery, support for spatial indexes, dynamic configuration
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A small issue of SQL standards

From a functional perspective, the core SQL support in all major and minor RDBMS-es is reasonably similar. In this light, it's sometimes quite disturbing to find how some very basic things work so differently across different products. Consider this simple statement:

SELECT  'a' /* this is a comment */ 'b'
FROM onerow

What should the result be? (You can assume that onerow is an existing table that contains one row)

It turns out popular RDBMS-es mostly disagree with one another.

In Oracle XE, we get this:

SELECT  'a' /* comment */ 'b'
ERROR at line 1:
ORA-00923: FROM keyword not found where expected

PostgreSQL 8.4 also treats it as a syntax error, and thus seems compatible with Oracle's behavior:

ERROR:  syntax error at or near "'b'"
LINE 1: SELECT 'a' /* this is a comment */ 'b'

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