sql how to transform data vertically - sql

Question

I have a 3 datbles Dealer, payment_type and dealer_payment_type
Dealer : dealer_id , dealer_name, dealer_address
1 | test | 123 test lane
2 | abc | abc lane
3 | def | def lane
Payment_type : paymenttype_id , paytype
1 | CHECK
2 | WIRE
3 | CREDIT
Dealer_Payment_type : DPT_id , dealer_id , payment_type_id
1 | 1 | 1
2 | 1 | 2
3 | 1 | 3
4 | 2 | 2
5 | 2 | 3
6 | 3 | 1
7 | 3 | 2
I have to write a query to get payment type info for each dealer , query needs to return data like this:
dealer_id , dealer_name , paytype
1 | test | check,wire,credit
2 | abc | wire,credit
3 | def | check,wire
OR
dealer_id , dealer_name , check , wire , credit
1 | test | true | true | true
2 | abc | false | true | true
3 | def | true | false | true

Answer 1

You did not specify what version of Oracle you are using.
If you are using Oracle 11g, then you can use the following.
To get the values into a single column, then you can use LISTAGG:
select d.dealer_id,
d.dealer_name,
listagg(p.paytype, ',') within group (order by d.dealer_id) as paytype
from dealer d
left join Dealer_Payment_type dp
on d.dealer_id = dp.dealer_id
left join payment_type p
on dp.payment_type_id = p.paymenttype_id
group by d.dealer_id, d.dealer_name;
See SQL Fiddle with demo
To get the values in separate columns, then you can use PIVOT:
select dealer_id, dealer_name,
coalesce("Check", 'false') "Check",
coalesce("Wire", 'false') "Wire",
coalesce("Credit", 'false') "Credit"
from
(
select d.dealer_id,
d.dealer_name,
p.paytype,
'true' flag
from dealer d
left join Dealer_Payment_type dp
on d.dealer_id = dp.dealer_id
left join payment_type p
on dp.payment_type_id = p.paymenttype_id
)
pivot
(
max(flag)
for paytype in ('CHECK' as "Check", 'WIRE' as "Wire", 'CREDIT' as "Credit")
)
See SQL Fiddle with Demo.
If you are not using Oracle 11g, then you can use wm_concat() to concatenate the values into a single row:
select d.dealer_id,
d.dealer_name,
wm_concat(p.paytype) as paytype
from dealer d
left join Dealer_Payment_type dp
on d.dealer_id = dp.dealer_id
left join payment_type p
on dp.payment_type_id = p.paymenttype_id
group by d.dealer_id, d.dealer_name;
To create the separate columns, then you can use an aggregate function with a CASE:
select dealer_id, dealer_name,
max(case when paytype = 'CHECK' then flag else 'false' end) "Check",
max(case when paytype = 'WIRE' then flag else 'false' end) "Wire",
max(case when paytype = 'CREDIT' then flag else 'false' end) "Credit"
from
(
select d.dealer_id,
d.dealer_name,
p.paytype,
'true' flag
from dealer d
left join Dealer_Payment_type dp
on d.dealer_id = dp.dealer_id
left join payment_type p
on dp.payment_type_id = p.paymenttype_id
)
group by dealer_id, dealer_name;
See SQL Fiddle with Demo