Hierarchy in sql table at 100th place [closed] - sql

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My SQL table looks like this
unit_number
name
party_number
1700
Facilities
000018727
1800
Human Resource
000018728
1801
PRO
000092293
1802
Human Resource
000092294
1803
Recruitment
000092295
1804
Learning & Development
000092296
1805
Administration
000100783
1900
Information Technology
000018729
1901
Information Technology
000092297
F&B
F&B
000045759
PRODUCT.
Product
000103719
I want to make a hierarchy structure of the above table where 1700,1800,1900...(at 100th place) are at level 1, while subsequent 1801, 1802 at level 2, level 3 resp.
What should be the query for that? I want to add a level column to the table

Answer 1

You could use the dense rank function as the following:
To make the not number values appear at the bottom of the hierarchy level use the following:
select *,
dense_rank() over
(order by
case
when try_cast(unit_number as int) is null
then 1 else 0
end,
isnull(try_cast(unit_number as int),99) % 100
) as h_level
from table_name
To make the not number values appear at the top of the hierarchy level use the following:
select *,
dense_rank() over
(order by
case
when try_cast(unit_number as int) is null
then 0 else 1
end,
isnull(try_cast(unit_number as int),1) % 100
) as h_level
from table_name
And if you want to consider the not number values to be in level 1 along with the (1700, 1800, ...), try this:
select *,
dense_rank() over
(order by isnull(try_cast(unit_number as int),0) % 100) as h_level
from table_name
See demo

Answer 2

You can try as follows:
UPDATE my_table
SET my_new_col = 1
WHERE unit_number LIKE '%00'
Then repeat with both values increased.
It can be done with a more complicated command in one UPDATE and some string manipulation and type casting, but it sounds like this will be a one-time operation so I don't see a lot of value in trying to do that.

Answer 3

Sounds like you're looking for the modulo operator:
/* Start Demo Data */
DECLARE #Units TABLE (Unit_Number NVARCHAR(10), Name NVARCHAR(50), Party_Number NVARCHAR(10), HierarchyLevel NVARCHAR(10))
INSERT INTO #Units (Unit_Number, Name, Party_Number) VALUES
('1700', 'Facilities ', '000018727'),
('1800', 'Human Resource ', '000018728'),
('1801', 'PRO ', '000092293'),
('1802', 'Human Resource ', '000092294'),
('1803', 'Recruitment ', '000092295'),
('1804', 'Learning & Development', '000092296'),
('1805', 'Administration ', '000100783'),
('1900', 'Information Technology', '000018729'),
('1901', 'Information Technology', '000092297'),
('F&B', 'F&B' , '000045759'),
('PRODUCT.','Product' , '000103719')
/* End Demo Data */
UPDATE #Units
SET HierarchyLevel = COALESCE((TRY_CAST(Unit_Number AS INT) % 100),0) + 1
FROM #Units
SELECT *
FROM #Units
Unit_Number Name Party_Number HierarchyLevel
------------------------------------------------------------------
1700 Facilities 000018727 1
1800 Human Resource 000018728 1
1801 PRO 000092293 2
1802 Human Resource 000092294 3
1803 Recruitment 000092295 4
1804 Learning & Development 000092296 5
1805 Administration 000100783 6
1900 Information Technology 000018729 1
1901 Information Technology 000092297 2
F&B F&B 000045759 1
PRODUCT. Product 000103719 1
Modulo returns the remainder after dividing a value by the value specified. In this case we want to know what the remainder is after dividing Unit_Number by 100. In order to start with a 1-indexed value as you requested we then add 1 to that.
100 returns 0, + 1: 1
101 returns 1, + 1: 2
We then just use this to update the HeierarchyLevel column.
When you're providing demo data for questions like this, it's very helpful to do so in an easily reusable format so folks can quickly work on your problem.