oracle SQL procedure updating table - oracle

Question

I need to update the the following columns in a table. males,females,infants and children using SQL procedure.from this column paxtype which has f,i,m,c.which is females,infants,males and children repectively.but am not able error ORA-00907: missing right parenthesis
update xxxx a set (a.INFANTS,a.MALES,a.CHILDREN,a.FEMALES)=
(SELECT b.PAXTYPE, COUNT (b.PAXTYPE) FROM xxxx b
(case ( count (b.PAXTYPE))
when ( count (b.PAXTYPE))='M'then 'a.males'
when ( count (b.PAXTYPE))='F' then 'a.females'
when ( count (b.PAXTYPE))='I' then 'a.infants'
when ( count (b.PAXTYPE))='C' then 'a.children'
END)
WHERE a.date_key = TO_CHAR (b.FLIGHTDATE, 'RRRRMMDD')
AND a.FLTNUM_KEY = TRIM (SUBSTR (b.flightnumber, 3))
AND a.origin = b.frm
AND a.destination = b.too
--and a.date_key=20170801
--and fightnumber = '100'
AND TRIM (a.cancelled) IS NULL
-- and rownum = 1
GROUP BY b.PAXTYPE;
)

Answer 1

It looks like you want a total count of each type, right? I think this is what you want to do.
update xxxx a set (a.INFANTS,a.MALES,a.CHILDREN,a.FEMALES)=
(SELECT
sum(case when b.PAXTYPE = 'I' then 1 else 0 end) as infants_count,
sum(case when b.PAXTYPE = 'M' then 1 else 0 end) as males_count,
sum(case when b.PAXTYPE = 'C' then 1 else 0 end) as children_count,
sum(case when b.PAXTYPE = 'F' then 1 else 0 end) as females_count
FROM xxxx b
WHERE a.date_key = TO_CHAR (b.FLIGHTDATE, 'RRRRMMDD')
AND a.FLTNUM_KEY = TRIM (SUBSTR (b.flightnumber, 3))
AND a.origin = b.frm
AND a.destination = b.too
--and a.date_key=20170801
--and fightnumber = '100'
AND TRIM (a.cancelled) IS NULL
-- and rownum = 1
GROUP BY b.PAXTYPE);