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He wasn't fetching using fetchrow_arrayref or fetchrow_hashref he was fetching with selectall_hashref and it does make a difference:

SQL> create table mje(mac varchar(10), comment varchar(10)); SQLRowCount returns -1 SQL> insert into mje values('1226', 'comment1'); SQLRowCount returns 1 SQL> insert into mje values('1226', 'comment2'); SQLRowCount returns 1 SQL> insert into mje values('1226', 'comment3'); SQLRowCount returns 1 SQL> select * from mje; +-----------+-----------+ | mac | comment | +-----------+-----------+ | 1226 | comment1 | | 1226 | comment2 | | 1226 | comment3 | +-----------+-----------+ SQLRowCount returns -1 3 rows fetched SQL>
perl -le 'use DBI; my $h = DBI->connect;nect; my $r = $h->selectall_ha +shref(q/select * from mje/, "mac"); use Data::Dumper; print Dumper($r +);' $VAR1 = { '1226' => { 'comment' => 'comment3', 'mac' => '1226' } };
perl -le 'use DBI; my $h = DBI->connect;nect; my $r = $h->selectall_ar +rayref(q/select * from mje/); use Data::Dumper; print Dumper($r);' $VAR1 = [ [ '1226', 'comment1' ], [ '1226', 'comment2' ], [ '1226', 'comment3' ] ];

If you use selectall_hashref or fetchall_hashref you need to provide a key column and if you have multiple rows where that key column has the same value you will lose some rows.

In reply to Re^2: MySQL hashes with same key by mje
in thread MySQL hashes with same key by jcrush

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    [hippo]: Yary: There are a few useful pointers in I need perl coding standards
    [hippo]: ... and a boatload of good stuff in On Coding Standards and Code Reviews
    [Yary]: Looking at system pm's, looks like it's "package" on the first line, then POD, then "use;use strict; use warnings; use modules..."
    [Yary]: ah thanks for those links
    [hippo]: Just bear in mind that all such ideas are subjective.
    [choroba]: There might be a different standard at the shop you write the code for.
    [choroba]: The order of package - (strict+warnings | warnings+strict) - modules makes sense, POD and strict-warnings order are not so important

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