How to obtain certain value from URL? [duplicate] - sql

Question

This question already has answers here:
SQL Server 2008 R2 - How to split my varchar column string and get 3rd index string
(4 answers)
Closed 7 years ago.
Given this URL:
www.google.com/hsisn/-#++#/valuetoretrive/+#(#(/.html
The value to is between 4th and 5th slash.
How to retrieve that particular value using SQL Server 2008?

Answer 1

There is no function in SQL server to get the nth occurrence of a value, the only function is CHARINDEX, which will retrieve the first instance after the specified starting position. So the only way to utilise this is to cascade each value found, i.e:
Find the position of 1st "/"
Find the position of the next "/" after the first one
Find the position of the next "/" after the second one
So each calculation requires the result of the previous one, which to get the 5th occurrence gets fairly messy, but not impossible if you use CROSS APPLY to reuse your results. Once you have the position of the 4th and 5th occurrence you can use SUBSTRING to extract the text:
SELECT t.url,
Value = SUBSTRING(t.url, p4.Position, p5.Position - p4.Position - 1)
FROM (SELECT url = 'URL:/www.google.com/hsisn/-#++#/valuetoretrive/+#(#(/.html') AS t
CROSS APPLY (SELECT 1 + CHARINDEX('/', url)) AS p1 (Position)
CROSS APPLY (SELECT 1 + CHARINDEX('/', url, p1.Position)) AS p2 (Position)
CROSS APPLY (SELECT 1 + CHARINDEX('/', url, p2.Position)) AS p3 (Position)
CROSS APPLY (SELECT 1 + CHARINDEX('/', url, p3.Position)) AS p4 (Position)
CROSS APPLY (SELECT 1 + CHARINDEX('/', url, p4.Position)) AS p5 (Position);
ADDENDUM
The other option you have, if you want more flexibility, i.e. get the text between the 50th and 51st occurrence, is to utilise a split function. The most efficient way to split strings is with a CLR function, but the next best T-SQL only method for this purpose is to use a numbers table to split your string, and in the absence of this create your own using stacked CTEs.
I will assume that you don't have a numbers table and use a stacked CTE in the interest of a complete working example.
CREATE FUNCTION dbo.Split (#StringToSplit VARCHAR(1000), #Delimiter CHAR(1))
RETURNS TABLE
AS
RETURN
( WITH N1 (N) AS (SELECT 1 FROM (VALUES (1), (1), (1), (1), (1), (1), (1), (1), (1), (1)) AS t (n)),
N2 (N) AS (SELECT 1 FROM N1 AS N1 CROSS JOIN N1 AS N2),
Numbers (N) AS (SELECT ROW_NUMBER() OVER(ORDER BY n1.N) FROM N1 CROSS JOIN N2 AS N2)
SELECT Position = ROW_NUMBER() OVER(ORDER BY n.N),
Value = SUBSTRING(#StringToSplit, n.N, ISNULL(NULLIF(CHARINDEX(#Delimiter, #StringToSplit, n.N + 1), 0), LEN(#StringToSplit)) - n.N)
FROM Numbers AS n
WHERE SUBSTRING(#Delimiter + #StringToSplit, n.N, 1) = #Delimiter
);
Which you can call fairly simply:
DECLARE #Table TABLE (URL VARCHAR(255) NOT NULL);
INSERT #Table VALUES ('URL:/www.google.com/hsisn/-#++#/valuetoretrive/+#(#(/.html');
SELECT s.*
FROM #Table AS t
CROSS APPLY dbo.Split(t.URL, '/') AS s;
Which gives you:
Position Value
---------------------
1 URL:
2 www.google.com
3 hsisn
4 -#++#
5 valuetoretrive
6 +#(#(
7 .htm
So you can simply select the 5th value from this by adding a where clause.:
DECLARE #Table TABLE (URL VARCHAR(255) NOT NULL);
INSERT #Table
VALUES
('URL:/www.google.com/hsisn/-#++#/valuetoretrive/+#(#(/.html'),
('URL:/www.google.com/hsisn/-#++#/valuetoretrive2/+#(#(/.html');
SELECT t.URL, s.Value
FROM #Table AS t
CROSS APPLY dbo.Split(t.URL, '/') AS s
WHERE s.Position = 5;

Answer 2

If you don't know before hand the lenght of the url or the value to retrieve or slash positions you can use this snipet
declare #uri varchar(max) = 'URL:/www.google.com/hsisn/-#++#/valuetoretrive/+#(#(/.html'
,#startAt int = 0
,#slashCount int = 0
while #slashCount < 5
begin
set #startAt = CHARINDEX('/',#uri);
set #slashCount = #slashCount + 1;
if (#slashCount = 5)
set #uri = SUBSTRING(#uri, 0, #startAt)
else
set #uri = SUBSTRING(#uri, #startAt + 1, LEN(#uri))
-- debug info
select #startAt, #slashCount, #uri
end
it ill decompose the string, getting slash positions until it find #4 and #5 slash and get anything between.
OUTPUT
5 1 www.google.com/hsisn/-#++#/valuetoretrive/+#(#(/.html
15 2 hsisn/-#++#/valuetoretrive/+#(#(/.html
6 3 -#++#/valuetoretrive/+#(#(/.html
6 4 valuetoretrive/+#(#(/.html
15 5 valuetoretrive
You also can get it using a cross apply instead of a while loop but this way you code ill not need to get big and messy to get anything after the n > 10, n-th slah.