Fetch column sum from database and print the output using static/dynamic queries

Question

I want to get the sum of the values in a column I ten print. I am executing the PHP code in the /devel/php page from the Devel module.

The query I want to execute is SELECT SUM(column_name) FROM table_name.

I tried the following code, but I get a Call to undefined function db_result() error.

$val = db_result(db_query('SELECT SUM(column_name) FROM {table_name}'));
print $val;

I also tried the following code, but I get a Object of class DatabaseStatementBase could not be converted to string in eval() error.

$query = db_select('table_name');
$query->addExpression('sum(column_name)', 'total');
$result = $query->execute();
print $result;

If I do not print $result, it works and executes, but I want to print the value.

How can I achieve this?

Answer 1

The first error is caused from the fact that Drupal 7 doesn't define db_result() anymore; it was used from Drupal 6.

The second error is caused from $query->execute() that returns a DatabaseStatementBase object, which cannot be convert to a string. (Converting the object to a string is what PHP does when an object is passed to print.)

You should use code similar to the following.

$query = db_select('table_name');
$query->addExpression('SUM(column_name)', 'total');
$result = $query->execute()->fetchField();