How do I use a variable for the name of a table in a DBI query?

Question

How do I using a variable for the name of a table in a DBI query? I know how to use placeholders as part of the where clause, but how do I do this for the table name?

I would like to do something like this:

 my $table_name='table1';
 my $query = $dbh_cgi->prepare("select * from ?");
 $query->execute($table_name);

So far, I end up getting a MySQL syntax error because DBI adds quotes around the name, table1.

Answer 1

One of the limitations of placeholders is that they can't be used for table names. Instead of using a placeholder, you can use a variable. To make sure the variable's contents are safe, use quote_identifier(), for example:

my $table_name='table1'; #-- Or get this from somewhere else
my $safe_table_name =  $dbh_cgi->quote_identifier($table_name);
my $query = $dbh_cgi->prepare("select * from $safe_table_name");
$query->execute();