Re: Problem with DBI and placeholders

  without using the variable $table it also fails with the same error

$sth = $dbh->prepare("SELECT * FROM ?");$sth->execute("test") && say "OK";


    On Friday, April 9, 2021, 2:12:01 PM GMT+2, mailing lists via beginners <[email protected]> wrote:  
 
  thanks Andrew 

I need to insert millions of rows so I need to have a good performance using placeholders 

    On Friday, April 9, 2021, 1:57:25 PM GMT+2, Andrew Solomon <[email protected]> wrote:  
 
 The ? is for quoting field values rather than entering table or field names. "SELECT * FROM $table" is probably what you want.
On Fri, Apr 9, 2021 at 12:49 PM mailing lists via beginners <[email protected]> wrote:

Hello,
I am having a problem with a very simple task and I don't see where the fault is. 

The first query works with problem but the second one fails with this error:
 ./test.pl 
OK 1
DBD::mysql::st execute failed: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''test'' at line 1 at ./test.pl line 28.END


Does anyone know where the problem is? 


     1    #!/usr/bin/perl
     2    use strict;
     3    use warnings;
     4    use 5.010;
     5    use DBI;
     6    
     7    my %db = (
     8       host     => 'mysql.local',
     9       user     => 'app',
    10       password => '12345678',
    11       db       => 'test_db',
    12    );
    13    
    14    my $dbh = DBI->connect(
    15                                'dbi:mysql:database='.$db{'db'}.';host='.$db{'host'}.';port=3306',
    16                                $db{'user'},
    17                                $db{'password'},
    18                                { AutoCommit => 1, },
    19                              )
    20                  or die "Can't connect to database: $DBI::errstr\n";
    21    
    22    
    23    my $sth = $dbh->prepare("SELECT * FROM test");
    24    $sth->execute() && say "OK 1";
    25    
    26    my $table="test";
    27    $sth = $dbh->prepare("SELECT * FROM ?");
    28    $sth->execute($table) && say "OK 2"
    29    
    30    say "END";







-- 
Andrew Solomon
Director, Geekuni
P: +44 7931 946 062
E: [email protected]