Custom field total in site header

[ubiquitas]

ok, I'm a beginner with XF and PHP so go easy...

I have a custom field (numeric), I want to show the total value from all users in my website header.

SQL to get the total (which works) is

SELECT
SUM(field_value) as MyTotal
FROM xf_user_field_value
WHERE field_id = 0x4B6472486F6C64696E67

so um, what next - I'm hoping there is a simple few lines of PHP I can dump in the appropriate template.

thanks for even reading this far

 

[ubiquitas]

sorted it - custom helper did the trick - thanks

 

[cdub]

Ok how do you do this? I don't know how to code.