i want to remove string after colon in sql server - sql

Question

-- i need data like this F11.20,F13.20,F14.10 in sql server
declare #S varchar(200) = ',F11.20:,F13.20:Sedative, hypnotic o,F14.10:Cocaine abuse, uncom';
select left(#S, charindex(':', #S, charindex(':', #S)+2)-2);

Answer 1

Any Split/Parse Function would do the trick, but you would have to perform secondary logic to clean the parsed string. That said, I modified a parse function to accept any two non-like delimiters (start/end). In this case a , and :
Also, being a Table-Valued-Function, it is easy to incorporate into a CROSS APPLY or as a stand-alone as illustrated below.
Example
Select NewString = Stuff((Select ',' +RetVal
From [dbo].[udf-Str-Extract](#S,',',':')
For XML Path ('')),1,1,'')
Returns
F11.20,F13.20,F14.10
The UDF if Interested
CREATE FUNCTION [dbo].[udf-Str-Extract] (#String varchar(max),#Delimiter1 varchar(100),#Delimiter2 varchar(100))
Returns Table
As
Return (
with cte1(N) As (Select 1 From (Values(1),(1),(1),(1),(1),(1),(1),(1),(1),(1)) N(N)),
cte2(N) As (Select Top (IsNull(DataLength(#String),0)) Row_Number() over (Order By (Select NULL)) From (Select N=1 From cte1 N1,cte1 N2,cte1 N3,cte1 N4,cte1 N5,cte1 N6) A ),
cte3(N) As (Select 1 Union All Select t.N+DataLength(#Delimiter1) From cte2 t Where Substring(#String,t.N,DataLength(#Delimiter1)) = #Delimiter1),
cte4(N,L) As (Select S.N,IsNull(NullIf(CharIndex(#Delimiter1,#String,s.N),0)-S.N,8000) From cte3 S)
Select RetSeq = Row_Number() over (Order By N)
,RetPos = N
,RetVal = left(RetVal,charindex(#Delimiter2,RetVal)-1)
From (Select *,RetVal = Substring(#String, N, L) From cte4) A
Where charindex(#Delimiter2,RetVal)>1
/*
Max Length of String 1MM characters
Declare #String varchar(max) = 'Dear [[FirstName]] [[LastName]], ...'
Select * From [dbo].[udf-Str-Extract] (#String,'[[',']]')
*/
EDIT Just to Help with the Visualization
If you executed the TVF alone:
declare #S varchar(200) = ',F11.20:,F13.20:Sedative, hypnotic o,F14.10:Cocaine abuse, uncom';
Select * From [dbo].[udf-Str-Extract](#S,',',':')
Returns
RetSeq RetPos RetVal
1 2 F11.20
2 10 F13.20
3 38 F14.10
EDIT 2 - Execute via Cross Apply
Declare #YourTable table (ID int,SomeString varchar(200))
Insert Into #YourTable values
(1,',F11.20:,F13.20:Sedative, hypnotic o,F14.10:Cocaine abuse, uncom'),
(2,',Z99.55:,Z25.10:Someother text')
Select A.ID
,B.*
From #YourTable A
Cross Apply (
Select NewString = Stuff((Select ',' +RetVal
From [dbo].[udf-Str-Extract](A.SomeString,',',':')
For XML Path ('')),1,1,'')
) B
Returns
ID NewString
1 F11.20,F13.20,F14.10
2 Z99.55,Z25.10

Answer 2

If the text you're extracting is always in the form of (letter, number, number, ., number, number) and there's always 3 instances of that text, then you could do this:
WITH
s1(string, ci) AS (SELECT #S, CHARINDEX(':', #S)),
s2(ci) AS (SELECT CHARINDEX(':', #S, ci+1) FROM s1),
s3(ci) AS (SELECT CHARINDEX(':', #S, ci+1) FROM s2)
SELECT
SUBSTRING(string, s1.ci-6, 6)+','+
SUBSTRING(string, s2.ci-6, 6)+','+
SUBSTRING(string, s3.ci-6, 6)
FROM s1, s2, s3;
Execution Plan:
It doesn't get any more efficient then that.
If its always the 6 characters before any instance of ":" you can grab a copy of NGrams8K and do this:
declare #S varchar(200) = ',F11.20:,F13.20:Sedative, hypnotic o,F14.10:Cocaine abuse, uncom';
SELECT NewString = STUFF
((SELECT ','+SUBSTRING(#S, position-6, 6)
FROM dbo.NGrams8k(#S, 1)
WHERE token = ':'
FOR XML PATH('')),1,1,'');
Another way using NGrams8K and a variable:
declare #S varchar(200) = ',F11.20:,F13.20:Sedative, hypnotic o,F14.10:Cocaine abuse, uncom';
declare #newstring varchar(100)='';
declare #S varchar(200) = ',F11.20:,F13.20:Sedative, hypnotic o,F14.10:Cocaine abuse, uncom';
declare #newstring varchar(100)='';
SELECT
#newstring +=
CASE #newstring WHEN '' THEN '' ELSE ',' END +SUBSTRING(#S, position-6, 6)
FROM dbo.NGrams8k(#S, 1)
WHERE token = ':';
SELECT #newstring;