Help for update query

Question

Hi, How I can split the column of code_full_desc and update in code1,code2 and code3 column which are blank. It should be split after first hyphen.
create table #desc (code_full_desc char(20), code1 char(4),code2 char(4), code3 char(6))
insert into #desc values ('CCCCA_AAAA_99_ECTRA','','','')
insert into #desc values ('DDDDA_BBBB_88_TRACT','','','')
---Results should be
code_full_desc                  code1   code2   code3
CCCCA_AAAA_99_ECTRA     AAAA   99        ECTRA
DDDDA_BBBB_88_TRACT      BBBB    88       TRACT

Answer 1

create table #desc (code_full_desc char(20), code1 char(4),code2 char(4), code3 char(6))
insert into #desc values ('CCCCA_AAAA_99_ECTRA','','','')
insert into #desc values ('DDDDA_BBBB_88_TRACT','','','')
select * from #desc
;with mycte as
SELECT row_number() Over(Partition by code_full_desc Order by code_full_desc) rn, code_full_desc, S.a.value('(/H/r)[4]', 'VARCHAR(100)') AS splitVal4
, S.a.value('(/H/r)[3]', 'VARCHAR(100)') AS splitVal3
, S.a.value('(/H/r)[2]', 'VARCHAR(100)') AS splitVal2
, S.a.value('(/H/r)[1]', 'VARCHAR(100)') AS splitVal1
,code1,code2,code3
FROM
SELECT *,CAST (N'<H><r>' + REPLACE(code_full_desc, '_', '</r><r>') + '</r></H>' AS XML) AS [vals]
FROM #desc) d
CROSS APPLY d.[vals].nodes('/H/r') S(a)
Update mycte
set
code1=splitVal2,
code2=splitVal3,
code3=splitVal4
WHERE rn=1
select * from #desc
drop table #desc