RE: [PHP] What's faster? MySQL Queries or PHP Loops?

[snip] I don't completely understand your terminology, but it's always faster to get all of your data with a single query rather than a query per loop. Of course, the difference is that it also requires more memory. In general, if you have the memory, use it. It will always be faster. [/snip] +1 However, there is a point of diminishing returns that we haven't spoken of. Dependent upon hardware and overhead, the size of the data to be manipulated (say 10k records vs. 100k records, in numbers or record size) will play an important part in speed. Always most efficient is the query once model. Don't forget that inserts and updates always take longer (especially with indexed columns). For mid-sized (and I know that for each of us that is defined differently) databases it's a real balancing act. One thing that needs to be pointed out here is that you can use PHP and MySQL to the fullest by planning data manipulation with PHP more efficiently. It takes more work up front to figure out all of the details but consider the following examples.... --------------------------------------------------------- $bar = 12; $sql = "SELECT foo FROM table1 WHERE conditions "; $result = mysql_query($sql, $connection); while($row = mysql_fetch_array($result)){ $insert = "INSERT INTO table2 (newFoo) VALUES ('" . ($bar + $row['foo']) . "') "; $insertResult = mysql_query($insert, $connection); } --------------------------------------------------------- or you could do this .... --------------------------------------------------------- $bar = 12; $sqlSelectCalculateAndInsert = "INSERT INTO table2 (newFoo) "; $sqlSelectCalculateAndInsert .= "SELECT (foo + " . $bar . ") FROM table WHERE conditions "; $result = mysql_query($sqlSelectCalculateAndInsert, $connection); --------------------------------------------------------- HTH