Execute the following script in Query Editor to generate a script for counting rows in all the schemas and tables of the database:

use AdventureWorks;

select 'select '''+s.name+'.'+o.name+''', count(*) from '
+s.name+'.'+o.name
from sys.objects o
join sys.schemas s
on o.schema_id=s.schema_id
where type = 'U'
order by s.name, o.name