Mulberry Monks,

Using DBI for mysql, I have a list of tables to query. Problem is, the list is supplied by someone else and may contain errors, meaning it may direct the script to query a table that does not exist. If this happens, it's important that the script not terminate in an error. Here's the typical code:

for $i (0 ..$#tables_to_query) {
     $sql = "select count(*) from ".$tables_to_query[$i].";";
     $sth = $dbh->prepare($sql) or die("Could not prepare!" . $dbh->er
+rstr);
     $sth->execute() or die("Could not execute!" . $dbh->errstr);
     $total = $sth->fetchrow_array();
     print "Total $i is $total\n";
}
[download]

So, I was thinking of two possibilities:

• Some SQL that will execute the query only if the table exists, so as not to generate any fatal mysql errors
• Some Perl that will trap any fatal mysql errors and let the script carry on

I found sql syntax that should work at the mysql site:

SELECT count(*) FROM r6019 WHERE EXISTS (SELECT * FROM r6019);
http://dev.mysql.com/doc/mysql/en/exists-and-not-exists-subqueries.html

but it produces an sql error.

What I don't want to do is use a SHOW TABLES and iterate through the results, because there are tens of thousands of tables in the database. I'm looking for something clean and simple.

Thanks

---

In reply to Best Perlish way to test if a mysql table exists? by punch_card_don

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