I have tried find the monthly total sales, total sendback values for every customer for 12 months. 

With other 2 subqueries then the query become use 26 subqueries for every row and SQL statement is very big. 

Then I created two sub-selects for sale and sendback totals... 

The result query is become shorter but execution time is bigger than 20-30 times. 

1. Is this normal
2. How can I return 0 if the subquery returns NULL..

EDIT:

```
(Select sum(chh2.cha_meblag)
 from dbo.CARI_HESAP_HAREKETLERI chh2
 where chh2.cha_normal_Iade=1 and
       chh2.cha_kod=ch.cari_kod and
       (chh2.cha_tarihi>='20130101' and chh2.cha_tarihi<='20130131')
) as Ocai

```