MySql. How can i get count from 2 tables

Question

I have 2 tables, TableA and TableB

TableA

IdA | Date       | Description  
--- | ---------- | -----------
1   | 2017-01-01 | Sometext1
2   | 2017-01-01 | Sometext2
3   | 2017-01-02 | Sometext3
4   | 2017-01-03 | Sometext4

---

TableB

IdB | IdA | Type
--- | --- | ----
1   | 1   | A  
2   | 1   | A
3   | 2   | A
4   | 2   | A
5   | 2   | B 
6   | 3   | B
7   | 4   | A

---

How can I get value like this :

Count(IdA) | Type        
---------- | ---- 
3          | A 

I have tried to code using INNER or LEFT JOIN like

SELECT COUNT(tablea.IdA), tableb.Type
FROM tablea INNER JOIN tableb
ON tablea.IdA=tableb.IdA
WHERE tableb.Type='A'

But it always get me like this

Count(IdA) | Type
---------- | ----
5          | A

I just want to count TableA row with WHERE clause from TableB. Is it possible to do something like that?

Answer 1

You probably want COUNT(DISTINCT col) .

Try this:

SELECT 
    COUNT(DISTINCT a.IdA), b.Type
FROM
    tablea a
        INNER JOIN
    tableb b ON a.IdA = b.IdA
WHERE
    b.Type = 'A'
GROUP BY b.type

Answer 2

Yes, you need distinct column ids (but here's an answer using alias)

SELECT COUNT(distinct A.IdA), B.Type
FROM tablea A
INNER JOIN tableb B ON (A.IdA = B.IdA)
WHERE B.Type = 'A'

And you don't even need to put an ON clause if you join by the same column name so, making the sql even shorter.

SELECT COUNT(distinct A.IdA), B.Type
FROM tablea A
INNER JOIN tableb B
WHERE B.Type = 'A'