Mysql sum not working

Question

i am trying to add up some records from a table, however, it isn't working properly, i.e. when i try var_dump to see what the value is showing i just get string(0) ""

Here is the code

 $current_wealth1 = mysql_query("SELECT SUM(estimated_wealth) as total_house_wealth FROM user_houses WHERE user_id='$user_id'");
var_dump($total_house_wealth);
$current_wealth = $ved_balance + $total_house_wealth;

In terms of output, i am just using conventional php print to output $current_wealth.

Any ideas, what could be the problem?

EDIT: Here is my current code, getting a syntax error on the second line

 $current_wealth1 = mysql_query("SELECT SUM(estimated_wealth) as total_house_wealth FROM user_houses WHERE user_id='$user_id'");
$total_house_wealth = mysql_fetch_array($current_wealth1)[0];
$current_wealth = $ved_balance + $total_house_wealth;

the function mysql_query doesn't work like that. just read the manual please, and take the RED HINTS about pdo/msqli to heart: php.net/manual/en/function.mysql-query.php — Nanne
– Nanne, Commented Jun 12, 2012 at 20:17

dynamic · Accepted Answer · 2012-06-12 20:55:18Z

2

You need of course to do

var_dump(mysql_fetch_array($current_wealth1));

Also most likely you get a syntax error becuase you don't have php 5.4. You can't do ...)[0];

edited Jun 12, 2012 at 20:55

answered Jun 12, 2012 at 20:17

dynamic

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Comments

Jamie · Accepted Answer · 2012-06-12 20:46:30Z

1

try splitting the fetch array to 2 lines to remove your syntax error?

$current_wealth1 = mysql_query("SELECT SUM(estimated_wealth) as total_house_wealth FROM user_houses WHERE user_id='$user_id'");
$total_house_wealth = mysql_fetch_array($current_wealth1);
$total_house_wealth = $total_house_wealth[0];
$current_wealth = $ved_balance + $total_house_wealth;

also, in your table structure, is user id a character string, or integer? if its an integer, then the userid='$user_id' in the WHERE clause shouldn't be single quoted (e.g. userid=$user_id *although you may want to sanitize the user_id var first*)

answered Jun 12, 2012 at 20:46

Jamie

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Comments

bluevector · Accepted Answer · 2012-06-12 20:18:26Z

1

$total_house_wealth isn't declare nor set with any value, so what you are seeing is expected behaviour. What you actually want is a different thing

$total_house_wealth = mysql_fetch_array($current_wealth1)[0];

answered Jun 12, 2012 at 20:18

bluevector

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6 Comments

Al Hennessey Over a year ago

thanks for the help, this is my first time doing mysql sum, so i didn't really think about fetching the array, although when i tried it, it said i got a syntax error on line 61, which is the line i put you code on. Any ideas?

bluevector Over a year ago

Put it immediately before var_dump($total_house_wealth); in your original example. Obviously, I can't see your line numbers.

Al Hennessey Over a year ago

ok i removed the var dump as i don't need it anymore, but now i get the error

Warning: mysql_fetch_array() expects parameter 1 to be resource, null given in C:\xampp\htdocs\Arken\profile1.php on line 61

I added my current code in my original post

bluevector Over a year ago

I didn't see the far right bit of you SQL statement. You have two problems with WHERE user_id='$user_id'. The first is syntactic, it needs to be WHERE user_id='{$user_id}' in order to reference the PHP variable $user_id. The second is SQL injection. You need to mysql_real_escape_string it first: `WHERE user_id = '{mysql_real_escape_string($user_id)}'

Al Hennessey Over a year ago

okay but if i keep the [0] at the end of the fetch_array, then i still get a syntax error on that line, if i remove it, i get an error in the html.

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