Create a Query to Combine Data from Two Tables with Similar data - sql-server-2012

Question

In need an aggregate result of two similar tables without getting duplicates.
The tables have similar structure. (date,billed_number,carrier_id,duration...)
tables are 2019-01-29 and 2019-01-30
I've tried UNION of the same query but I get duplicate entries.
select billed_number, sum(CASE WHEN [account_billed_duration] > 0 THEN 1 END) AS completed
from alex4..[2019-01-29]
where billed_number = '702640'
and carrier_id = 171
group by billed_number
union all
select billed_number, sum(CASE WHEN [account_billed_duration] > 0 THEN 1 END) AS completed
from alex4..[2019-01-30]
where billed_number = '702640'
and carrier_id = 171
group by billed_number
In this example I'm only using tables ([2019-01-29] and [2019-01-30])
I also need to be able to combine more than two tables.
Result:
billed_number,completed
702640 3735
702640 3539
Expected Result:
billed_number, completed
702640 7274

Answer 1

Use union not union all indeed combine all results with duplicates

Answer 2

thank you for the reply. I actually tried both UNION and UNION ALL and got the same result.
I was up last night until I figured it out.
A sub query did the trick...
SELECT distinct billed_number , sum(completed)as comp , FROM (
SELECT [billed_number],
sum(CASE WHEN [account_billed_duration] > 0 THEN 1 END) AS completed,
sum(CASE WHEN [account_billed_duration] = 0 THEN 1 END) AS failed
FROM alex4..[2019-01-29]
where billed_number = '702640'
and carrier_id = 171
group by billed_number --,account_billed_duration
UNION
SELECT [billed_number],
sum(CASE WHEN [account_billed_duration] > 0 THEN 1 END) AS completed,
sum(CASE WHEN [account_billed_duration] = 0 THEN 1 END) AS failed
FROM alex4..[2019-01-30]
where billed_number = '702640'
and carrier_id = 171
group by billed_number --, account_billed_duration
) Q
group by billed_number
Once again thank you for the reply :-)