Yes, but it was my intention to check whether there was a difference between the 'bind' and the 'inline' versions over cgi and mod-perl execution using very similar syntax in both versions, the only difference being the use of the '?' placeholder.

I did not expect any difference (placeholders being emulated in DBD:MySQL), nor could I indeed find any significant difference, leading me to conclude that there is no interference between cgi/mod-perl as far as using place-holders is concerned.

So the reason must be found somewhere else.

Update: I tried using the $sth->bind_param(1, $parameter) to see if it made a difference: nope, all remained the same (within the to be expected statistical variations).

So either it must be a data-issue (seems rather far-fetched) or something with the OP's code (but we haven't seen it, so I cannot comment).