Question

I have two tables as follows :-

           Table 1                      Table 2 
         date     value             date     value 
         1120101   v11              1120102   v21
         1120202   v12              1120303   v22  
         1120203   v13              1120104   v23  

what is the sql query to get following output

        date         value 
       1120101       (v11)
       1120102       (v12+v21)
       1120103       (v13+v22)
       1120104       ( v23)  

I tired following query but failed to get desired output

select table1.date,
       table2.date,
       table1.delta+table2.delta as delta 
from table1,
     table2   
where table1.date=table2.date;

thanks in advance .

Answer 1

SELECT date, SUM(value)
FROM
(
    SELECT date, value FROM table1
    UNION ALL
    SELECT date, value FROM table2
) a
GROUP BY date

• SQLFiddle Demo (data is different but idea is the same)