If you can't connect to MySQL over PHP from your localhost, then try something like:

In the Windows/System32/drivers/etc/hosts file remove the entry like this: 
::1             localhost 

and make sure you still have:       localhost

Taken from here.

Question is, how to get count records in union query?

For example, we have this query:

select count(*) from hdxbh_content
union all
select count(*) from jos_users

As a result, we will have two records:



And we want to get result as one record, 905, how?

Like this:

select ((select count(*) from hdxbh_content) + (select count(*) from jos_users)) count

Taken from here.