Returning the sum of a select statement SQL -

i have created select statement:

select arii2.amount        ar_customer arc2     inner join ar_customer_site         arcs2   on arc2.customer_id = arcs2.customer_id , arcs2.customer_id = arc2.customer_id     inner join ar_customer_system       arcsys2  on arcs2.customer_site_id = arcsys2.customer_site_id     inner join ar_branch                arb2     on arb2.branch_id = arc2.branch_id     inner join ar_invoice               arin2    on arin2.customer_site_id = arcs2.customer_site_id     inner join ar_invoice_item          arii2    on arii2.invoice_id = arin2.invoice_id        inner join sy_system                sysy2   on arcsys2.system_id = sysy2.system_id                           arin2.invoice_date > dateadd(year, -1, getdate())     , arc2.customer_number = '300000'              , arii2.[description] ('warranty credit')     or arii2.[description] = ('warranty credit t') group arii2.amount 

that returns following results.

2031.00 1458.98 1272.50 620.00 160.00 

my thought put sum around amount , return desired value of 5542.48 (the total of values).

select      sum(arii2.amount)        ar_customer arc2     inner join ar_customer_site         arcs2   on arc2.customer_id = arcs2.customer_id , arcs2.customer_id = arc2.customer_id     inner join ar_customer_system       arcsys2  on arcs2.customer_site_id = arcsys2.customer_site_id     inner join ar_branch                arb2     on arb2.branch_id = arc2.branch_id     inner join ar_invoice               arin2    on arin2.customer_site_id = arcs2.customer_site_id     inner join ar_invoice_item          arii2    on arii2.invoice_id = arin2.invoice_id        inner join sy_system                sysy2   on arcsys2.system_id = sysy2.system_id                           arin2.invoice_date > dateadd(year, -1, getdate())     , arc2.customer_number = '300000'              --and arin2.invoice_number = '204686'     , arii2.[description] ('warranty credit')     or arii2.[description] = ('warranty credit t') group arii2.amount, arii2.[description] 

which returned following results not looking for.

-10155.00 -7294.90 -6362.50 -3100.00 -800.00 

as on appreciated!

you getting multiple rows because of group by. remove line, , 1 total sum.