SQL - Referencing 3 tables - sql

Question

This is in relation to my survey application for our team. I have 3 tables in my database related to this problem.
I apologize if the database is not fully normalized.
TBL_CHURCH columns:
1 FAM_CHURCH_SACRMNT_NUM (Primary Key) Int(15)
2 RSPONDNT_NUM
3 SURVYR_NUM
4 QN_NUMBER
5 CHRCHFAMLY_NAME
6 CHRCHFAMLY_ISBAPTIZED
Sample row based on order of columns above:
1 2 3 4 5 6
6422164 76826499 5712 362 Serio Tecson Jr. Yes
TBL_INTRVW columns:
1 QN_NUMBR (Primary Key)
2 SURVYR_NUM
3 ZONE_NUM
4 RSPONDNT_NUM
Sample row based on order of columns above:
1 2 3 4
362 5712 11 76826499
TBL_AREA columns:
1 BRGY_ZONE_NUM (Primary Key)
2 BRGY_CODE
Sample row based on order of columns above:
1 2
11 2A
21 2A
31 2A
The field CRCHFAMLY_ISBAPTIZED has only two values. A "Yes" or a "No" and each row has a QN_NUMBR value that is referenced to TBL_INTRVW and each QN_NUMBR on TBL_INTRVW has a unique ZONE_NUM that is referenced to TBL_AREA and that ZONE_NUM has a corresponding BRGY_CODE. Each BRGY_CODE have at least 2 ZONE_NUM values
My problem is that I want to count the number of people baptized in a given area.
The output more or less should look like this:
(The output is collected from the 3 different ZONE_NUM)
Zone Name Num of People Baptized
2A 20
I'm having what trouble what to use in my SQL statements. Should I use a WHERE within an INNER JOIN? And how do I go about in my SELECT statements?

Answer 1

SELECT c.BRGY_ZONE_NUM,count(a.CHRCHFAMLY_ISBAPTIZED) as [Num of People Baptized]
from TBL_CHURCH a
left join
TBL_INTRVW b
on a.QN_NUMBER=b.QN_NUMBER
left join
TBL_AREA c
on b.ZONE_NUM=cRGY_ZONE_NUM
where a.CHRCHFAMLY_ISBAPTIZED='Yes'
group by c.BRGY_ZONE_NUM
I dont see Zone Name column on the three table, so i used BRGY_ZONE_NUM