+=head1 SUBROUTINES
+
+=over 4
+
+=item str2time_sql [ DRIVER_NAME ]
+
+Returns a function to convert to unix time based on database type, such as
+"EXTRACT( EPOCH FROM" for Pg or "UNIX_TIMESTAMP(" for mysql. You are
+responsible for the closing parenthesis yourself. Don't let it down. It's a
+sensitive parenthesis.
+
+You can pass an optional driver name such as "Pg", "mysql" or
+$dbh->{Driver}->{Name} to return a function for that database instead of
+the current database.
+
+=cut
+
+sub str2time_sql {
+ my $driver = shift || driver_name;
+
+ return 'UNIX_TIMESTAMP(' if $driver =~ /^mysql/i;
+ return 'EXTRACT( EPOCH FROM ' if $driver =~ /^Pg/i;
+
+ warn "warning: unknown database type $driver; guessing how to convert ".
+ "dates to UNIX timestamps";
+ return 'EXTRACT(EPOCH FROM ';
+
+}
+
+=back
+