TSQL GROUP BY part of string - tsql

Question

I have a simple query. Something like this:
SELECT l.list_name, COUNT(order_id)
FROM orders o JOIN lists l ON l.order_id=o.order_id
WHERE l.list_name LIKE 'orders_1%' or l.list_name LIKE 'orders_2%'
GROUP BY l.list_name
The situation looks like this: overight a stored procedure is updating the lists table, but it chops lists in parts if there are more than 1000 orders.
If I have 1200 orders with criteria or list 'orders_1', then my procedure will create two lists: 'orders_1_1' 'and orders_1_2', the first having 1,000 and second 200 orders.
So when I run my query to count those orders I will get results like so:
list_name count
orders_1 100
orders_1_more_than_100_1 1000
orders_1_more_than_100_2 200
orders_2 400
orders_3_1 1000
orders_3_2 1000
orders_3_3 420
orders_3_more_than_100_1 1000
orders_3_more_than_100_2 900
orders_3_more_than_200_1 1000
orders_3_more_than_200_2 1000
orders_3_more_than_200_3 100
orders_4 200
orders_4_more_than_300 200
The result I would like to get should look like this:
list_name count
orders_1 100
orders_1_more_than_100 1200
orders_2 400
orders_3 2420
orders_3_more_than_100 1900
orders_3_more_than_200 2100
orders_4 200
orders_4_more_than_300 200
So that it will sum all lists that start the same.
Any ideas on that? :)
These are the exact values that I have in my list_names column:
WYS_AUT_PISMO_NR_6
WYS_AUT_PISMO_NR_5_POWYZEJ_240
WYS_AUT_PISMO_NR_5_DO_240
WYS_AUT_PISMO_NR_4_POWYZEJ_240_5
WYS_AUT_PISMO_NR_4_POWYZEJ_240_4
WYS_AUT_PISMO_NR_4_POWYZEJ_240_3
WYS_AUT_PISMO_NR_4_POWYZEJ_240_2
WYS_AUT_PISMO_NR_4_POWYZEJ_240_1
WYS_AUT_PISMO_NR_4_DO_240
WYS_AUT_PISMO_NR_3_POWYZEJ_240
WYS_AUT_PISMO_NR_3_DO_240
WYS_AUT_PISMO_NR_2_POWYZEJ_240
WYS_AUT_PISMO_NR_2_DO_240
WYS_AUT_PISMO_NR_1
What I want is to group them like so:
WYS_AUT_PISMO_NR_6
WYS_AUT_PISMO_NR_5_POWYZEJ_240
WYS_AUT_PISMO_NR_5_DO_240
WYS_AUT_PISMO_NR_4_POWYZEJ_240 /*here I must group those 5 lists*/
WYS_AUT_PISMO_NR_4_DO_240
WYS_AUT_PISMO_NR_3_POWYZEJ_240
WYS_AUT_PISMO_NR_3_DO_240
WYS_AUT_PISMO_NR_2_POWYZEJ_240
WYS_AUT_PISMO_NR_2_DO_240
WYS_AUT_PISMO_NR_1

Answer 1

This monstruous expression will isolate string starting from beginning of parameter to last _ if there are more than one underscores:
select case when len (l.list_name) - len (replace (l.list_name, '_', '')) > 1
then left(l.list_name,
len (l.list_name) - charindex('_', reverse(l.list_name)))
else l.list_name
end
Alternatively you might strip 'orders_' from string, replace underscore with dot and convert it to float, then to int to remove decimals, and then back to string using this monstrosity:
select 'orders_' + cast (cast (cast (
replace (substring (#str, 8, 100), '_', '.')
as float) as int) as varchar(100))
To avoid repeating this blobs, use derived table instead of lists:
SELECT l.TrimmedListName, COUNT(order_id)
FROM orders o
JOIN
(
select lists.*,
-- Remove optional list continuation number
case when len (list_name) - len (replace (list_name, '_', '')) > 1
then left(list_name,
len (list_name) - charindex('_', reverse(list_name)))
else list_name
end AS TrimmedListName
from lists
) l ON l.order_id=o.order_id
WHERE (l.list_name LIKE 'orders_1%' or l.list_name LIKE 'orders_2%')
GROUP BY l.TrimmedListName

Answer 2

try something like
select substring(l.list_name, 0, 8), count(order_Id)
FROM orders o JOIN lists l ON l.order_id=o.order_id
WHERE l.list_name LIKE 'orders_1%' or l.list_name LIKE 'orders_2%'
group by substring(l.list_name, 0, 8)
Updated answer for the updated question:
select newColName, COUNT(order_id)
from
(
select case when GetSubstringCount(l.list_name, '_', '') > 1 then
SUBSTRING(l.list_name, 0, len(l.list_name) - 2)
else l.list_name end as NewColName
, order_Id
FROM orders o JOIN lists l ON l.order_id=o.order_id
WHERE l.list_name LIKE 'orders_1%' or l.list_name LIKE 'orders_2%'
) mySubTable
group by newColName
You'll need something like This to create the GetSubstringCount method