How to clean a string and extract number postfixes in T-SQL - sql-server

Question

I have a string that consists of a name and in most cases it has a postfix with one or two numbers at the end. This number-postfix should be cut off from the name. One number represents a status and should be extracted. If there are two numbers it is the seconde from the right, if there is one number it is the first from the right. These numbers are seperated by an underscore. Underscores can also be used within the name.
The result should be a column with the clearname and the extracted status.
I tried to solve the problem with the standard string functions like Substring, Charindex, Patindex, LEN and son on. But my approach became very bulky quickly and hard to maintain. I wonder if there is an elegant solution with the usual SQl-Server capabilities (if possible without installing extras for regex).
SELECT _data.myStr
-- , ... AS clearname /*String cleaned from number_postfixes*/
-- , ... AS Status /*second number from the right*/
FROM (
SELECT 'tree_leafs_offer_2_1' AS myStr --clearname: tree_leafs_offer; cut off: _2_1; extracted status: 2
UNION
SELECT 'tree_leafs_offer_2_10' AS myStr --clearname: tree_leafs_offer_2_10; cut off: _2_10; extracted status: 2
UNION
SELECT 'tree_leafs_offer_2_2' AS myStr --clearname: tree_leafs_offer; cut off: _2_2; extracted status: 2
UNION
SELECT 'tree_leafs_offer_1150_1' AS myStr --clearname: tree_leafs_offer; cut off: _1150_1; extracted status: 1150
UNION
SELECT 'tree_leafs_offer_1150_10' AS myStr --clearname: tree_leafs_offer; cut off: _1150_10; extracted status: 1150
UNION
SELECT 'builder_bundle_less_xl_1' AS myStr --clearname: builder_bundle_less_xl; cut off: _1; extracted status: 1
UNION
SELECT 'builder_bundle_less_xl_10' AS myStr --clearname: builder_bundle_less_xl; cut off: _10; extracted status: 10
UNION
SELECT 'static_components_wolves_10_4' AS myStr --clearname: static_components_wolves; cut off: _10_4; extracted status: 4
UNION
SELECT 'coke_0_boring_components_bundle_grant_1' AS myStr --clearname: oke_0_boring_components_bundle_grant; cut off: _1; extracted status: 1
UNION
SELECT 'coke_0_soccer18_end_1_4h_101' AS myStr --clearname: coke_0_soccer18_end_1_4h; cut off: _101; extracted status: 101
UNION
SELECT 'coke_0_late_downsell_bundle_high_114' AS myStr --clearname: coke_0_late_downsell_bundle_high; cut off: _114; extracted status: 114
UNION
SELECT 'itembundle_mine_bundle_small' AS myStr --clearname: itembundle_mine_bundle_small; cut off: <nothing>; extracted status: NULL
) AS _data
As-Is Result:
-----------------
myStr:
---------------------------------------
builder_bundle_less_xl_1
builder_bundle_less_xl_10
coke_0_boring_components_bundle_grant_1
coke_0_late_downsell_bundle_high_114
coke_0_soccer18_end_1_4h_101
itembundle_mine_bundle_small
static_components_wolves_10_4
tree_leafs_offer_1150_1
tree_leafs_offer_1150_10
tree_leafs_offer_2_1
tree_leafs_offer_2_10
tree_leafs_offer_2_2
To-Be Result (two new columns):
-------------------
clearname: |Status
----------------------------------------------
builder_bundle_less_xl | 1
builder_bundle_less_xl | 10
coke_0_boring_components_bundle_grant | 1
coke_0_late_downsell_bundle_high | 114
coke_0_soccer18_end_1_4h | 101
itembundle_mine_bundle_small |NULL
static_components_wolves | 10
tree_leafs_offer |1150
tree_leafs_offer |1150
tree_leafs_offer | 2
tree_leafs_offer | 2
tree_leafs_offer | 2

Answer 1

To be honest: this format is awful! If this is not a one-time-action you really should try to change this before you have to deal with it.
But - if you have to stick with this - you might give this a try:
EDIT: resolved a bad computation of the status position...
DECLARE #tbl TABLE(ID INT IDENTITY,myStr VARCHAR(1000));
INSERT INTO #tbl VALUES
('tree_leafs_offer_2_1')
,('tree_leafs_offer_2_10')
,('tree_leafs_offer_2_2')
,('tree_leafs_offer_1150_1')
,('tree_leafs_offer_1150_10')
,('builder_bundle_less_xl_1')
,('builder_bundle_less_xl_10')
,('static_components_wolves_10_4')
,('coke_0_boring_components_bundle_grant_1')
,('coke_0_soccer18_end_1_4h_101')
,('coke_0_late_downsell_bundle_high_114')
,('itembundle_mine_bundle_small');
The query
WITH cte AS
(
SELECT t.ID
,t.myStr
,A.[key] AS Position
,A.[value] AS WordFragment
,B.CastedToInt
FROM #tbl t
CROSS APPLY OPENJSON(N'["' + REPLACE(t.myStr,'_','","') + '"]') A
CROSS APPLY(SELECT TRY_CAST(A.[value] AS INT)) B(CastedToInt)
)
SELECT ID
,myStr
,STUFF(
(SELECT CONCAT('_',cte2.WordFragment)
FROM cte cte2
WHERE cte2.ID=cte.ID
AND cte2.Position<=A.PositionHighestNonInt
ORDER BY cte2.Position
FOR XML PATH('')
),1,1,'') AS ClearName
,(SELECT cte3.CastedToInt FROM cte cte3 WHERE cte3.ID=cte.ID AND cte3.Position=A.PositionHighestNonInt+1) AS [Status]
FROM cte
CROSS APPLY (
SELECT ISNULL(MAX(x.Position),1000)
FROM cte x
WHERE x.ID=cte.ID AND x.CastedToInt IS NULL
) A(PositionHighestNonInt)
GROUP BY ID,myStr,PositionHighestNonInt;
The result
+----+---------------------------------------+--------+
| ID | ClearName | Status |
+----+---------------------------------------+--------+
| 1 | tree_leafs_offer | 2 |
+----+---------------------------------------+--------+
| 2 | tree_leafs_offer | 2 |
+----+---------------------------------------+--------+
| 3 | tree_leafs_offer | 2 |
+----+---------------------------------------+--------+
| 4 | tree_leafs_offer | 1150 |
+----+---------------------------------------+--------+
| 5 | tree_leafs_offer | 1150 |
+----+---------------------------------------+--------+
| 6 | builder_bundle_less_xl | 1 |
+----+---------------------------------------+--------+
| 7 | builder_bundle_less_xl | 10 |
+----+---------------------------------------+--------+
| 8 | static_components_wolves | 10 |
+----+---------------------------------------+--------+
| 9 | coke_0_boring_components_bundle_grant | 1 |
+----+---------------------------------------+--------+
| 10 | coke_0_soccer18_end_1_4h | 101 |
+----+---------------------------------------+--------+
| 11 | coke_0_late_downsell_bundle_high | 114 |
+----+---------------------------------------+--------+
| 12 | itembundle_mine_bundle_small | NULL |
+----+---------------------------------------+--------+
The idea:
Provide your data in a mockup table
Use a trick with OPENJSON to get the string split and find parts which can be cast to INT.
Find the highest non-int fragment. The Status will be the next index
With v2017 you could use STRING_AGG, but with v2016 we have to use a XML-based trick to concatenate all fragments before the [Status].

Answer 2

One possible approach is to use string replacement and JSON capabilities of SQL Server 2016+. Each row is reversed and transformed into a valid JSON array ('tree_leafs_offer_2_1' is transformed into '["1","2","reffo","sfael","eert"]' for example). Then you can easily check if the first and the second items are valid numbers using JSON_VALUE(<json_array>, '$[0]'), JSON_VALUE(<json_array>, '$[1]') and TRY_CONVERT(). This will work if you have maximum two numbers from the right.
Input:
CREATE TABLE #Data (
myStr varchar(max)
)
INSERT INTO #Data
(MyStr)
VALUES
('tree_leafs_offer_2_1'),
('tree_leafs_offer_2_10'),
('tree_leafs_offer_2_2'),
('tree_leafs_offer_1150_1'),
('tree_leafs_offer_1150_10'),
('builder_bundle_less_xl_1'),
('builder_bundle_less_xl_10'),
('static_components_wolves_10_4'),
('coke_0_boring_components_bundle_grant_1'),
('coke_0_soccer18_end_1_4h_101'),
('coke_0_late_downsell_bundle_high_114'),
('itembundle_mine_bundle_small')
T-SQL:
SELECT
LEFT(myStr, LEN(myStr) - CHARINDEX('_', REVERSE(myStr))) as ClearName,
REVERSE(LEFT(REVERSE(myStr), CHARINDEX('_', REVERSE(myStr)) - 1)) AS Status
FROM (
SELECT
CASE
WHEN
TRY_CONVERT(int, REVERSE(JSON_VALUE(CONCAT('["', REPLACE(STRING_ESCAPE(REVERSE(MyStr), 'json'), '_', '","'), '"]'), '$[1]'))) IS NULL AND
TRY_CONVERT(int, REVERSE(JSON_VALUE(CONCAT('["', REPLACE(STRING_ESCAPE(REVERSE(MyStr), 'json'), '_', '","'), '"]'), '$[0]'))) IS NULL
THEN CONCAT(myStr, '_0')
WHEN
TRY_CONVERT(int, REVERSE(JSON_VALUE(CONCAT('["', REPLACE(STRING_ESCAPE(REVERSE(MyStr), 'json'), '_', '","'), '"]'), '$[1]'))) IS NULL AND
TRY_CONVERT(int, REVERSE(JSON_VALUE(CONCAT('["', REPLACE(STRING_ESCAPE(REVERSE(MyStr), 'json'), '_', '","'), '"]'), '$[0]'))) IS NOT NULL
THEN MyStr
ELSE LEFT(myStr, LEN(myStr) - CHARINDEX('_', REVERSE(myStr)))
END AS myStr
FROM #Data
) fixed
ORDER BY MyStr
Output:
----------------------------------------------
ClearName Status
----------------------------------------------
builder_bundle_less_xl 1
builder_bundle_less_xl 10
coke_0_boring_components_bundle_grant 1
coke_0_late_downsell_bundle_high 114
coke_0_soccer18_end_1_4h 101
itembundle_mine_bundle_small 0
static_components_wolves 10
tree_leafs_offer 1150
tree_leafs_offer 1150
tree_leafs_offer 2
tree_leafs_offer 2
tree_leafs_offer 2