How to pull out information from a long string of data - sql

Question

I have this data point:
455-U-202007302233,455-L-202007302233,422-U-202008011052,422-L-202008011052,857-U-202008041142,857-L-202008061215
Column: ,[t810str]
How would I be able to modify column [t810str] in order to pull out the last comma set before 857?
Desired Result = 422-L-202008011052

Answer 1

First you need to implement some kind of splitter that respects ordinal position (STRING_SPLIT does not). I'm therefore going to make use of DelimitedSplit8k_LEAD. Then you can split the value, and use LAG to get the prior value. Finally you can filter on where the item has a value LIKE '857%' but the previous does not:
WITH CTE AS(
SELECT DS.Item,
LAG(DS.Item) OVER (PARTITION BY YourColumn ORDER BY DS.itemNumber) AS PrevItem
FROM (VALUES('455-U-202007302233,455-L-202007302233,422-U-202008011052,422-L-202008011052,857-U-202008041142,857-L-202008061215'))V(YourColumn)
CROSS APPLY dbo.DelimitedSplit8K_LEAD(V.YourColumn,',') DS)
SELECT C.PrevItem
FROM CTE C
WHERE C.Item LIKE '857%'
AND C.PrevItem NOT LIKE '857%';

Answer 2

Based on your data and the assumption that items are 18 characters (your data do not indicate otherwise):
DECLARE #t AS NVARCHAR(255) = '455-U-202007302233,455-L-202007302233,422-U-202008011052,422-L-202008011052,857-U-202008041142,857-L-202008061215';
SELECT RIGHT(LEFT(#t,CHARINDEX(',857',#t)-1),18)

Answer 3

Using cross apply (which you can also rewrite using a CTE or a subquery for readability). This removes everything after first occurrence of 857 and then grabs the last set that's left. So even if you have multiple 857 and varying length of delimited strings, this should work
select *, right(remind , charindex (',' ,reverse(remind))-1)
from t t1
cross apply (select stuff(col, charindex(',857',col), len(col),'') as remind) t2
DEMO

Answer 4

Another solution use a recursive CTE
DECLARE #Var VARCHAR(200) = '455-U-202007302233,455-L-202007302233,422-U-202008011052,422-L-202008011052,857-U-202008041142,857-L-202008061215';
WITH CTE AS
(
SELECT 0 N, LEFT(#Var, CHARINDEX(',', #Var)-1) Part,
RIGHT(#Var, LEN(#Var) - CHARINDEX(',', #Var)) Remind
UNION ALL
SELECT N + 1,
LEFT(Remind, CHARINDEX(',', Remind) - 1),
RIGHT(Remind, LEN(Remind) - CHARINDEX(',', Remind))
FROM CTE
WHERE CHARINDEX(',', Remind) <> 0
)
SELECT TOP 1 Part
FROM CTE
WHERE LEFT(Remind, 3) = '857'
ORDER BY N;
Demo

Answer 5

Implemented with string functions (and assuming your data items can have variable length :-) it might look a bit confusing (therefore I'd prefer #Larnu's answer):
DECLARE #string VARCHAR(2000) = '455-U-202007302233,455-L-202007302233,422-U-202008011052,422-L-202008011052,857-U-202008041142,857-L-202008061215'
SELECT SUBSTRING(#string, CHARINDEX(',857',#string) - CHARINDEX(',', REVERSE( LEFT(#string, PATINDEX('%,857%',#string) - 1)) ) + 1, CHARINDEX(',', REVERSE( LEFT(#string, PATINDEX('%,857%',#string) - 1)))-1 )
Parts of the latter separated:
DECLARE #string VARCHAR(2000) = '455-U-202007302233,455-L-202007302233,422-U-202008011052,422-L-202008011052,857-U-202008041142,857-L-202008061215'SELECT CHARINDEX(',857',#string)
SELECT LEFT(#string, PATINDEX('%,857%',#string) - 1)
SELECT REVERSE( LEFT(#string, PATINDEX('%,857%',#string) - 1) )
SELECT CHARINDEX(',', REVERSE( LEFT(#string, PATINDEX('%,857%',#string) - 1)) )