jokerfool Posted August 23, 2012 Share Posted August 23, 2012 I have a table named 'comments', and I would like to use PHP to return to the browser how many comments are already stored within the database. Cheers Link to comment https://forums.phpfreaks.com/topic/267470-total-number-of-rows/ Share on other sites More sharing options...
spiderwell Posted August 23, 2012 Share Posted August 23, 2012 http://php.net/manual/en/function.mysql-num-rows.php Link to comment https://forums.phpfreaks.com/topic/267470-total-number-of-rows/#findComment-1371736 Share on other sites More sharing options...
Jessica Posted August 23, 2012 Share Posted August 23, 2012 If all you need is the number of comments on a post, use COUNT(). SELECT COUNT(comment_id) AS total_comments FROM comments WHERE post_id = x Link to comment https://forums.phpfreaks.com/topic/267470-total-number-of-rows/#findComment-1371806 Share on other sites More sharing options...
ManiacDan Posted August 23, 2012 Share Posted August 23, 2012 You can also use SQL_CALC_FOUND_ROWS if you're paginating the results. Link to comment https://forums.phpfreaks.com/topic/267470-total-number-of-rows/#findComment-1371813 Share on other sites More sharing options...
Jessica Posted August 23, 2012 Share Posted August 23, 2012 Quote You can also use SQL_CALC_FOUND_ROWS if you're paginating the results. +1 Link to comment https://forums.phpfreaks.com/topic/267470-total-number-of-rows/#findComment-1371814 Share on other sites More sharing options...
ManiacDan Posted August 23, 2012 Share Posted August 23, 2012 SQL_CALC_FOUND_ROWS won't work on ultra-large result sets, like billions of rows. It's best to use some other sort of counting/estimation tactic separate from your query for that. Link to comment https://forums.phpfreaks.com/topic/267470-total-number-of-rows/#findComment-1371818 Share on other sites More sharing options...
Barand Posted August 23, 2012 Share Posted August 23, 2012 If you want the number of rows in a table use "SELECT COUNT(*) FROM tablename". Mysql does not have to read every row to get this value as it would if you were to use mysql_num_rows(). Link to comment https://forums.phpfreaks.com/topic/267470-total-number-of-rows/#findComment-1371909 Share on other sites More sharing options...
ManiacDan Posted August 23, 2012 Share Posted August 23, 2012 Quote If you want the number of rows in a table use "SELECT COUNT(*) FROM tablename". Mysql does not have to read every row to get this value as it would if you were to use mysql_num_rows(). Only true for certain storage engines which store row_count in the table's metadata. IIRC, it works instantly on MyISAM, but slower on InnoDB. But the OP was asking for number of comments per topic anyway, I think. Link to comment https://forums.phpfreaks.com/topic/267470-total-number-of-rows/#findComment-1371910 Share on other sites More sharing options...
Barand Posted August 23, 2012 Share Posted August 23, 2012 He just wants to know how many comments are stored in the database Link to comment https://forums.phpfreaks.com/topic/267470-total-number-of-rows/#findComment-1371911 Share on other sites More sharing options...
ManiacDan Posted August 24, 2012 Share Posted August 24, 2012 Quote He just wants to know how many comments are stored in the database I figured he didn't actually mean "total comments in the table," but we may never know. Link to comment https://forums.phpfreaks.com/topic/267470-total-number-of-rows/#findComment-1372012 Share on other sites More sharing options...
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