SQL SERVER Update and Insert to different table that has duplicate value - sql

Question

I have two tables, Table A and B. I want to update the RAM_PARENT_CATEGORY_CODE column of Table A with the value from Table B. However, for category_alert_ctr 55 and 82. There are 2 possible RAM_PARENT_CATEGORY_CODE from Table B.
I want to insert a new row in Table A to accommodate both of those RAM_PARENT_CATEGORY_CODE (CRM1b and crm1c). Then update the value with the correct value from Table B.
So the expected result will be :
55 | crm1b1 | CRM1 | CRM1b
83 | crm1b1 | CRM1 | crm1c
82 | Area1 | BuildApp | OFC01
84 | Area1 | BuildApp | OFC02
Do you have any idea to do this? Thanks.

Answer 1

Use the MERGE statement to insert such rows from Table B that are not in Table A, and update those that are in Table A.To check, click here.
with
a as (
select
*,
row_number() over(
partition by category_alert_ctr order by (select 0)
) rn
from #A
),
b as (
select
*,
row_number() over(
partition by RAM_CATEGORY_CODE, RAM_GROUP
order by RAM_PARENT_CATEGORY_CODE
) rn,
row_number() over(
order by RAM_CATEGORY_CODE, RAM_PARENT_CATEGORY_CODE
) cac_offset
from #B
),
m as (
select
a.category_alert_ctr,
iif(b.rn = 1 and a.category_alert_ctr is not null,
a.category_alert_ctr,
max(a.category_alert_ctr) over() + b.cac_offset) new_cac,
b.RAM_CATEGORY_CODE, b.RAM_GROUP, b.RAM_PARENT_CATEGORY_CODE, b.rn
from b
left join a
on b.RAM_CATEGORY_CODE = a.ram_category_code and
b.RAM_GROUP = a.RAM_GROUP and b.rn = a.rn
)
merge a
using m
on a.RAM_CATEGORY_CODE = m.RAM_CATEGORY_CODE and
a.RAM_GROUP = m.RAM_GROUP and a.rn = m.rn
when matched then
update set
a.category_alert_ctr = m.new_cac,
a.RAM_PARENT_CATEGORY_CODE = m.RAM_PARENT_CATEGORY_CODE
when not matched then
insert(category_alert_ctr, ram_category_code,
RAM_GROUP, RAM_PARENT_CATEGORY_CODE)
values(m.new_cac, m.RAM_CATEGORY_CODE,
m.RAM_GROUP, m.RAM_PARENT_CATEGORY_CODE)
;

Answer 2

to handle multiple matches, use row_number() to generate a unique numbering for matching
UPDATE A
SET RAM_PARENT_CATEGORY_CODE = B.RAM_PARENT_CATEGORY_CODE
FROM (
SELECT *, RN = ROW_NUMBER() OVER (PARTITION BY RAM_CATEGORY_CODE, RAM_GROUP
ORDER BY RAM_CATEGORY_CODE)
FROM TABLEA
) A
INNER JOIN (
SELECT *, RN = ROW_NUMBER() OVER (PARTITION BY RAM_CATEGORY_CODE, RAM_GROUP
ORDER BY RAM_CATEGORY_CODE)
FROM TABLEB
) B
ON A.RAM_CATEGORY_CODE = B.RAM_CATEGORY_CODE
AND A.RAM_GROUP = B.RAM_GROUP
AND A.RN = B.RN

Answer 3

If necessary to update the category_alert_ctr column.To check, click here.
declare #A table(
category_alert_ctr int,
ram_category_code varchar(30),
RAM_GROUP varchar(30),
RAM_PARENT_CATEGORY_CODE varchar(30)
);
insert #A values
(25, 'HLTHLIC_FF', 'HEALTHLIC', null),
(28, 'M16', 'QBL', null),
(55, 'crm1b1', 'CRM1', null),
(55, 'crm1b1', 'CRM1', null),
(82, 'Area1', 'BuildApp', null),
(82, 'Area1', 'BuildApp', null);
declare #B table(
RAM_CATEGORY_CODE varchar(30),
RAM_GROUP varchar(30),
RAM_PARENT_CATEGORY_CODE varchar(30)
);
insert #B values
('HLTHLIC_FF', 'HEALTHLIC', 'HLTHLC_RST'),
('M16', 'QBL', 'EPA'),
('crm1b1', 'CRM1', 'CRM1b'),
('crm1b1', 'CRM1', 'crm1c'),
('Area1', 'BuildApp', 'OFC01'),
('Area1', 'BuildApp', 'OFC02');
with
a as (
select
*,
iif(
row_number() over(
partition by category_alert_ctr order by (select 0)
) = 1,
category_alert_ctr,
max(category_alert_ctr) over() +
row_number() over(order by category_alert_ctr) -
dense_rank() over(order by category_alert_ctr)
) new_category_alert_ctr,
row_number() over(
partition by category_alert_ctr order by (select 0)
) rn
from #A
),
b as (
select
*,
row_number() over(
partition by RAM_CATEGORY_CODE, RAM_GROUP
order by RAM_PARENT_CATEGORY_CODE
) rn
from #B
)
update a
set a.category_alert_ctr = a2.new_category_alert_ctr,
a.RAM_PARENT_CATEGORY_CODE = b.RAM_PARENT_CATEGORY_CODE
from a
join a a2
on a.category_alert_ctr = a2.category_alert_ctr and a.rn = a2.rn
join b
on a.RAM_CATEGORY_CODE = a.RAM_CATEGORY_CODE and
a.RAM_GROUP = b.RAM_GROUP and a.rn = b.rn
;
select * from #A;