How efficient is MySQL

[Mittineague]

Well, I am feeling very pleased about using

    SELECT ts_opts.option_name
         , ts_opts.option_value
      FROM ( SELECT option_name
                  , option_value
               FROM $wpdb->options
              WHERE autoload NOT LIKE 'yes'
                AND option_name LIKE 'rss\_%\_ts'
        $no_query_less
           ) AS ts_opts
    UNION ALL
    SELECT non_ts_rss_opts.option_name
         , NULL
      FROM ( SELECT option_name
               FROM $wpdb->options
              WHERE autoload NOT LIKE 'yes'
                AND option_name LIKE 'rss\_%'
                AND option_name NOT LIKE 'rss\_%\_ts'
        $no_query_less
           ) AS non_ts_rss_opts 

Where $no_query_less is either empty or

ORDER BY option_id DESC LIMIT " . ($query_limit / 2) 

The experience has taught me more about how MySQL works and how to optimize a query to minimize resource use.

Unfortunately the same plugin user is still having problems, this time a syntax error near FROM ( SELECT option_name , option_value
He has MySQL 4 something so I need to find out if there are syntactial differences between different versions and/or engines.

Another day, another puzzle.

[Dan Grossman]

Subqueries weren't supported by MySQL until 4.1

[Mittineague]

Ah, that would explain it. Thanks for the info. I did a bit of poking around the MySQL docs last night but didn't find that.

(As I go off to find a way to add more fail-safe robustness)