Perl + SQL question

[c4n]

In my Perl script I use

while ($h = $sth->fetchrow_hashref) {
do this and that with $h->{colum1}, $h->{colum2} etc.
}

to print out the results of a SELECT statement.

My question is how can I know (get the number of) how many results (rows) are returned before I begin the "while" command?

Thank you!

 

[goBoating]

I don't think you can. Seems like I remember reading somewhere that the the record sets are typically returned by db servers in chunks or groups of records.(I don't remember where I read it, maybe on the dbi-users list??) Two fairly straight forward approaches might be....

1 - pull all results into a memory structure before you do any ouput... using the memory structure as a temp container while you play with the data.

2 - execute two queries, first to get result set size and second to output the records as appropriate.

select count(*) from ... where condition....

select field1, field2 from ... where same condition.....

'hope this helps

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[c4n]

Thanks, i will probably use the 2nd suggestion.

I did run by this statement in MySQL reference, but can't get it working ...

SELECT CALC_FOUND_ROWS * FROM table_name WHERE id > 100 LIMIT 10;
SELECT FOUND_ROWS();