SQL function parsing out text from a column - sql

Question

i have a table with some text i want to parse out and i'm very close to the solution but its not quite there. i have a column called indicatornumerator and i want to parse out similar to below ie i want to each of the values in between the square brackets onto a new row. as you can see from the output below i am getting a repeat for the first value after the minus. this does not happen for those which do not have a minus.
my function is as follows:
alter function fn_breakdown (#string varchar(max))
returns #breakdown table
(
originalstr varchar(max),
breakdownstr varchar(max)
)
as
begin
while charindex('r',#string,1) >0
begin
insert into #breakdown
select #string,
SUBSTRING(#string,CHARINDEX('r',#string,1),CHARINDEX(']',#string,1)-CHARINDEX('r',#string,1))
set #string = right(#string,len(#string)-CHARINDEX(')',#string,1))
end
return
end
a second thing i would like to do is to return those after the minus as a minus value rather eg. -R101 instead of R101 as i need to subtract those values later.
Any help much appreciated
the below should create a temporary table and will show you the output i'm getting. you will see that one of the rows duplicates. i am looking to have one row for each value beginning with 'R' in the indicatornumerator column
create table #temped2
(
indicatornumerator varchar(max)
)
insert into #temped2
select '(SUM([R4]) + SUM([R1010])) - (SUM([R1035]) + SUM([R1034]))'
select * from #temped2
cross apply fn_breakdown(indicatornumerator)

Answer 1

Download a copy of ngrams8k and then:
-- sample data
DECLARE #yourtable TABLE (IndicatorNumerator varchar(1000));
INSERT #yourtable
SELECT 'SUM([R4]) + SUM([R1010]) - SUM([R50]) + SUM([R200])' UNION ALL
SELECT 'SUM([R554]) + SUM([R210]) - SUM([R500]) + SUM([R999])';
-- Solution
SELECT
t.IndicatorNumerator,
breakdownstr = substring(t.IndicatorNumerator, ng.position+1, n.d-ng.position-1)
FROM #yourtable t
CROSS APPLY dbo.ngrams8k(t.IndicatorNumerator, 2) ng
CROSS APPLY (VALUES (charindex(']',t.IndicatorNumerator, ng.position+1))) n(d)
WHERE ng.token = '[R';
Returns:
IndicatorNumerator breakdownstr
-------------------------------------------------------- --------------
SUM([R4]) + SUM([R1010]) - SUM([R50]) + SUM([R200]) R4
SUM([R4]) + SUM([R1010]) - SUM([R50]) + SUM([R200]) R1010
SUM([R4]) + SUM([R1010]) - SUM([R50]) + SUM([R200]) R50
SUM([R4]) + SUM([R1010]) - SUM([R50]) + SUM([R200]) R200
SUM([R554]) + SUM([R210]) - SUM([R500]) + SUM([R999]) R554
SUM([R554]) + SUM([R210]) - SUM([R500]) + SUM([R999]) R210
SUM([R554]) + SUM([R210]) - SUM([R500]) + SUM([R999]) R500
SUM([R554]) + SUM([R210]) - SUM([R500]) + SUM([R999]) R999

Answer 2

Please try this code if you are using SQL Server 2016 and avove
;WITH cte_date
AS
(
SELECT indicatornumerator, REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(indicatornumerator,'(',''),')',''),'[',''),']',''),'SUM',''),'- ','-') ParsedData
FROM #temped2
)
SELECT *
FROM cte_date
CROSS APPLY STRING_SPLIT(ParsedData, ' ')
WHERE [VALUE] != '+';
Below script will work older than sql server 2016
CREATE FUNCTION [dbo].[StrParse]
(#delimiter CHAR(1),
#csv NTEXT)
RETURNS #tbl TABLE(Keys NVARCHAR(255))
AS
BEGIN
DECLARE #len INT
SET #len = Datalength(#csv)
IF NOT #len > 0
RETURN
DECLARE #l INT
DECLARE #m INT
SET #l = 0
SET #m = 0
DECLARE #s VARCHAR(255)
DECLARE #slen INT
WHILE #l <= #len
BEGIN
SET #l = #m + 1--current position
SET #m = Charindex(#delimiter,Substring(#csv,#l + 1,255))
IF #m <> 0
SET #m = #m + #l
--insert #tbl(keys) values(#m)
SELECT #slen = CASE
WHEN #m = 0 THEN 255
ELSE #m - #l
END
IF #slen > 0
BEGIN
SET #s = Substring(#csv,#l,#slen)
INSERT INTO #tbl
(Keys)
SELECT #s
END
SELECT #l = CASE
WHEN #m = 0 THEN #len + 1
ELSE #m + 1
END
END
RETURN
END
GO
;WITH cte_date
AS
(
SELECT indicatornumerator, REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(indicatornumerator,'(',''),')',''),'[',''),']',''),'SUM',''),'- ','-'),'+ ','') ParsedData
FROM #temped2
)
SELECT *
FROM cte_date
CROSS APPLY dbo.StrParse(' ', ParsedData)
go