converting comma separated value to multiple rows - sql

Question

I have a table like this:
ID NAME Dept_ID
1 a 2,3
2 b
3 c 1,2
Department is another table having dept_id and dept_name as columns. i want result like,
ID Name Dept_ID
1 a 2
1 a 3
2 b
3 c 1
3 c 2
any help please?

Answer 1

You can do it as:
--Dataset Preparation
with tab(ID, NAME,Dept_ID) as (Select 1, 'a', '2,3' from dual
UNION ALL
Select 2, 'b','' from dual
UNION ALL
Select 3, 'c' , '1,2' from dual)
--Actual Query
select distinct ID, NAME, regexp_substr(DEPT_ID,'[^,]+', 1, level)
from tab
connect by regexp_substr(DEPT_ID,'[^,]+', 1, level) is not null
order by 1;
Edit:
based on which column i need to join? in one table i have comma
separated ids and in other table i have just ids
with tab(ID, NAME,Dept_ID) as (Select 1, 'a', '2,3' from dual
UNION ALL
Select 2, 'b','' from dual
UNION ALL
Select 3, 'c' , '1,2' from dual) ,
--Table Dept
tbl_dept (dep_id,depname) as ( Select 1,'depa' from dual
UNION ALL
Select 2,'depb' from dual
UNION ALL
Select 3,'depc' from dual
) ,
--Seperating col values for join. Start your query from here using with clause since you already have the two tables.
tab_1 as (select distinct ID, NAME, regexp_substr(DEPT_ID,'[^,]+', 1, level) col3
from tab
connect by regexp_substr(DEPT_ID,'[^,]+', 1, level) is not null
order by 1)
--Joining table.
Select t.id,t.name,t.col3,dt.depname
from tab_1 t
left outer join tbl_dept dt
on t.col3 = dt.dep_id
order by 1

Answer 2

with tmp_tbl as(
select
1 ID,
'a' NAME,
'2,3' DEPT_ID
from dual
union all
select
2 ID,
'b' NAME,
'' DEPT_ID
from dual
union all
select
3 ID,
'c' NAME,
'1,2' DEPT_ID
from dual)
select
tmp_out.ID,
tmp_out.NAME,
trim(tmp_out.DEPT_ID_splited)
from(
select
tmp.ID,
tmp.NAME,
regexp_substr(tmp.DEPT_ID,'[^,]+', 1, level) DEPT_ID_splited
from
tmp_tbl tmp
connect by
regexp_substr(tmp.DEPT_ID,'[^,]+', 1, level) is not null) tmp_out
group by
tmp_out.ID,
tmp_out.NAME,
tmp_out.DEPT_ID_splited
order by
tmp_out.ID,
tmp_out.DEPT_ID_splited