SQL query to calculate total per month as a column - sql

Question

I am stuck on a SQL query. I am using PostgreSQL. I need to get the total for each month for all states.
table A
--------------------------------------------------------
created | Name | Agent_id | Total
--------------------------------------------------------
3/14/2013 | Harun | 1A | 5
3/14/2013 | Hardi | 2A | 20
4/14/2013 | Nizar | 3A | 30
5/14/2013 | moyes | 4A | 20
table B
----------------------------
Agent_id| state_id
----------------------------
1A | 1
2A | 1
3A | 1
4A | 2
table C
----------------------------
state_id | State
----------------------------
1 | Jakarta
2 | Singapore
3 | Kuala lumpur
DESIRED RESULT:
-----------------------------------------------------------------------------------------------
No |State | Januari | February | March | April | Mei ... December| Total
-----------------------------------------------------------------------------------------------
1 |Jakarta |0 |0 |25 | 30 | 0 ... | 55
2 |Singapore |0 |0 | 0 | 0 | 20 ... | 20
3 |Kuala Lumpur |0 |0 | 0 | 0 | 0 ... | 0

Answer 1

to have all state with no data in table A / B you have to use OUTER JOIN
to complete #bma answer
select
no,
state,
sum(case when month = 1 then total else 0 end) as januari,
sum(case when month = 2 then total else 0 end) as februari,
sum(case when month = 3 then total else 0 end) as mars,
sum(case when month = 4 then total else 0 end) as april,
sum(case when month = 5 then total else 0 end) as may,
sum(case when month = 6 then total else 0 end) as juni,
sum(case when month = 7 then total else 0 end) as juli,
sum(case when month = 8 then total else 0 end) as august,
sum(case when month = 9 then total else 0 end) as september,
sum(case when month = 10 then total else 0 end) as october,
sum(case when month = 11 then total else 0 end) as november,
sum(case when month = 12 then total else 0 end) as december,
sum(coalesce(total,0)) as total
from (
select
c.state_id as no,
extract(month from created) as month,
state,
sum(total) as total
from tablec c
left join tableb b on ( b.state_id = c.state_id)
left join tablea a on ( a.agent_id = b.agent_id)
group by c.state_id,state,month
) sales
group by no,state;
SQL Fiddle demo

Answer 2

Actually i do not know much about postgres sql this is a try see if this works
try this
Select EXTRACT(MONTH FROM TIMESTAMP table A.created) ,
table C.State , SUM(Total) From table A , table B , table C
Where table A.Agent_id = table B.Agent_id
And table B.state_id = table C.state_id
Group by table C.State , EXTRACT(MONTH FROM TIMESTAMP table A.created);

Answer 3

Something like the following should give you results like your sample results. I'm not sure what the "No" column was though. This query is untested.
select state,
sum(case when mm = 1 then total else 0 end) as jan,
sum(case when mm = 2 then total else 0 end) as feb,
sum(case when mm = 3 then total else 0 end) as mar,
sum(case when mm = 4 then total else 0 end) as apr,
sum(case when mm = 5 then total else 0 end) as may,
sum(case when mm = 6 then total else 0 end) as jun,
sum(case when mm = 7 then total else 0 end) as jul,
sum(case when mm = 8 then total else 0 end) as aug,
sum(case when mm = 9 then total else 0 end) as sep,
sum(case when mm = 10 then total else 0 end) as oct,
sum(case when mm = 11 then total else 0 end) as nov,
sum(case when mm = 12 then total else 0 end) as dec,
sum(total) as total
from (
select extract(month from created) as mm,
state,
sum(total) as total
from table_a
group by state,mm
) s
group by state;