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Full Discussion: Getting Rows from a MySQL Table with max values?
Top Forums Programming Getting Rows from a MySQL Table with max values? Post 302633841 by Corona688 on Wednesday 2nd of May 2012 02:03:10 PM
Old 05-02-2012
I'm not saying a full table-scan will happen as much as, the result of an indexed query can't be different than what a table scan could do. (Except in order, which isn't guaranteed anyway, ORDER BY sorts after the fact.) Therefore, it won't use information from the index to know the maximum in advance. Your second query, where you just 'select max(..) from ...' would be able to use the index.

I'm not sure index is required either, as much as the performance could be quite poor if it isn't.
 

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LEARN ABOUT LINUX

fc-query

FC-QUERY(1)                                                                                                                            FC-QUERY(1)

NAME

       fc-query - query font files

SYNOPSIS

       fc-query [ -Vh ]
           [ -i index | --index index ] [ -f format | --format format ] [ --version ] [ --help ] font-file ...

DESCRIPTION

       fc-query queries font-file(s) using the normal fontconfig rules and prints out font pattern for each face found.  If --index is given, only
       one face of each file is queried, otherwise all faces are queried.

OPTIONS

       This program follows the usual GNU command line syntax, with long options starting with two dashes (`-').  A summary of options is included
       below.

       -i --index index
              Only query face indexed index of each file.

       -f --format format
              Format output according to the format specifier format.

       -V --version
              Show version of the program and exit.

       -h --help
              Show summary of options.

       font-file
              Query font-file for font faces.

RETURN CODES

       fc-query returns error code 0 for successful parsing, or 1 if any errors occured or if at least one font face could not be opened.

SEE ALSO

       fc-scan(1) FcFreeTypeQuery(3) FcPatternFormat(3) fc-cat(1) fc-cache(1) fc-list(1) fc-match(1) fc-pattern(1)

       The fontconfig user's guide, in HTML format: /usr/share/doc/fontconfig/fontconfig-user.html.

AUTHOR

       This manual page was updated by Behdad Esfahbod <behdad@behdad.org>.

                                                                   16 April 2012                                                       FC-QUERY(1)
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