Mysql split the column values based on the joining table

Question

I need a query to find the count based on the multiple table. Please Check the below details

I am having 3 tables as table_1, table_2, table_3 and table_1 is the primary table, and other 2 are inherited from the primary. these table has the common value of profile_id column. Check this sample query counter

SELECT COUNT(profile_id) 
from table_1 
WHERE profile_id IN (SELECT profile_id FROM table_2)

the above query returns the count based on the table_2 profile id . But i need query with all the tables separately like as below

SELECT COUNT(profile_id) as table_2count, 
       COUNT(profile_id) as table_3count 
FROM table_1 WHERE (the two condition) 

In above query table_2count is based on the table_2 profiles and table_3count will be based on the table_3. How can i merge these values into single query. Please suggest some methods to find out the count values.

Answer 1

You can use 2 subqueries to achieve that:

 SELECT
      t1.*,   -- get all data from t1 + two counts from t2 and t3
      (SELECT COUNT(t2.profile_id) 
       FROM table_2 t2 
       WHERE t2.profile_id = t1.profile_id) as count2,
      (SELECT COUNT(t3.profile_id) 
       FROM table_3 t3 
       WHERE t3.profile_id = t1.profile_id) as count3
    FROM table_1 t1
    WHERE <your conditions for table_1 go here>

Answer 2

If profile_id is unique in table_1 and you have foreign keys in table_2 and table_3 , you don't really need to join back with table_1, what you need is something like this.

SELECT 
(SELECT COUNT(distinct profile_id) FROM table_2) table_2count,
(SELECT COUNT(distinct profile_id) FROM table_3) table_3count

If you really need a join or there are no FKs defined, you can use this

SELECT
    COUNT(distinct t2.profile_id) table_2count,
    COUNT(distinct t3.profile_id) table_3count
FROM table_1 t1
    LEFT JOIN table_2 t2 on t1.profile_id = t2.profile_id
    LEFT JOIN table_3 t3 on t1.profile_id = t3.profile_id