select count(*) from select

问题:

I am trying to get row count from the following query. I get only row count as 1 but there are 35 records. Could you please let me know how to get the count from inner query?

Thank you

SELECT COUNT(*)(SELECT DISTINCT a.my_id, a.last_name, a.first_name, b.temp_val
                FROM Table_A a INNER JOIN Table_B b on a.a_id = b.a_id)

回答1:

You're missing a FROM and you need to give the subquery an alias.

SELECT COUNT(*) FROM 
(
  SELECT DISTINCT a.my_id, a.last_name, a.first_name, b.temp_val
   FROM dbo.Table_A AS a 
   INNER JOIN dbo.Table_B AS b 
   ON a.a_id = b.a_id
) AS subquery;