Re: Calculating Totals from table columns without a second query to the DB

Hi Jay, MySQL deserves some more respect. It's language is quite potent. Have you had a look on COUNT()? It is suited well for... well, counting. I would like to be able to sum up a collumns values already in MySQL. The following query will sum up all values of the column 'id': SELECT @idsum:=(IFNULL(@idsum, id)+id), id FROM yourtable; Now a question to the PHP/MySQL experienced: Why does this type of query not work in combination with PHP? I am using query above as $query and do the following standard procedure: $result = mysql_query($query); while ($row = mysql_fetch_row($result)) { echo join(", ", $row) . "<br>"; }; But MySQLs variable seems to be reset for each row. Is there any other access method on a query that can cope with it properly? Timo Am Freitag den, 6. September 2002, um 17:32, schrieb Jay Blanchard:

[thinking out loud] For small result sets where I am looking for column totals I generally issue 2 queries to the database, one for the data and one for the totals. This works fine, but for some things the database returns 100's or 1000's of records. To make this easier to use I "page" the records, showing an appropriate number of records for each page. The records for each page returned like so (normal); while($row = mysql_fetch_object($result)){ print("<td>" . $row->value . "</td>\n"); print("<td>" . $row->another_value . "</td>\n"); } The PHB would now like a "totals per page" and a "grand totals". Easy enough with 3 queries each time the page is called, one for the records, one for the page totals, (using proper LIMIT queries) and one for the grand totals, but awfully inefficient and intensive. I suppose I could do something like this; while($row = mysql_fetch_object($result)){ print("<td>" . $row->value . "</td>\n"); print("<td>" . $row->another_value . "</td>\n"); $value1 = $value1 + $row->value; $value2 = $value2 + $row->another_value; } [/thinking out loud] In the process of typing this out I of course realized that this would work very well. Even if the database contains NULL values they are treated as zero. This gets me back to 2 queries, one of which only has to be issued once (the one for the grand totals, the results can be held in variables and echo'd or printed as needed). It also seems to be very efficient as the $value variables will only be doing a one time math operation each time through the while loop. For smaller results sets all on one page the same type of operation could be used for the grand totals as well, working the whole report down to a single query. I use a lot of crosstab queries where totals are needed along the bottom or right side, you can only do one within the original query. The other totals are left to another query ... usually. This should be a lesson to us all, we all try to over-compicate the issue sometimes. Usually a look at the docs/manual/FAQ/other-text-intensive-method-of-delivering-information will deliver the solution to a problem while some thought slowed to a reasonable speed (such as me typing out the problem above) will also allow natural logic to occur, producing a solution. Break down the process into managable portions, solving each portion before moving on to the next. Challenge; Can this be made as simple for rows too? Peace and I HTH someone else! Jay Hard work has a future payoff. Laziness pays off NOW. *****************************************************

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