Indeed there isn't any way to dynamically set table names in DBI, or indeed in most databases. The reason why comes down to what a ->prepare() is actually doing. (Note: this is somewhat platform specific, so YMMV here). The prepare tells the database to get the SQL ready and parsed so that it can be executed with a variety of parameters in the where clause. This is an efficiency issue for the DB, and there is no way to dynamically avoid it.

So, what can you do?

• To get the row-count you can either do the count(*) (as you mentioned) or retrieve all rows and count them
• To get by the dynamic table problem you can write a simple sub (see below) that takes the table-name and returns you the SQL.
• That sub can be linked with the cute DBI method $dbh->selectrow_array() which can remove the need for the prepare/execute combination and save you a few lines of code

sub make_sql($) { return "SELECT COUNT(*) FROM $_[0]"; }

if ($dbh->selectrow_array(make_sql($tablename))) {
      # do stuff
      }
[download]

A final note: something seems buggy to me in using the selectrow_array method directly in the if condition, but I can't put my finger on what it is. You might want to break it into a separate variable $count = $dbh->selectrow_array(make_sql($tablename));

Hth!
-Tats

Update: I just realized that my response is nearly identical to hmerril's just above....

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