As a side note you are making a mistake with this SQL query. Take a quick look at Exploits of a mom, SQL_injection. The DBI documetation has a section on Placeholders and bind variables, and links to references about SQL injection also Bobby Tables -> Perl.

Your code:

my $quer = "SELECT checklist.id FROM group_management,User_group_manag
+ement_mapping,profiles,checklist,checklist_group_mapping WHERE User_g
+roup_management_mapping.userid = $usr and  profiles.userid = User_gro
+up_management_mapping.userid and group_management.id =User_group_mana
+gement_mapping.groupid and checklist_group_mapping.checklist_id = che
+cklist.id and checklist_group_mapping.group_id = group_management.id"
+;
my $query = $dbh -> prepare($quer);
$query-> execute();
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Becomes:

my $SQLquery = "
    SELECT checklist.id 
    FROM group_management, User_group_management_mapping, profiles, ch
+ecklist,checklist_group_mapping 
    WHERE User_group_management_mapping.userid = ? 
    and  profiles.userid = User_group_management_mapping.userid 
    and group_management.id = User_group_management_mapping.groupid 
    and checklist_group_mapping.checklist_id = checklist.id
    and checklist_group_mapping.group_id = group_management.id";

my $sth = $dbh->prepare( $SQLquery );
$sth->execute( $usr );
[download]

Note that I've changed some of the variable names you used, and made it a little easier to read IMHO.