SQL - Selecting portion of a string - sql

Question

If I have a simple table where the data is such that the rows contains strings like:
/abc/123/gyh/tgf/345/6yh/5er
In SQL, how can I select out the data between the 5th and 6th slash? Every row I have is simply data inside front-slashes, and I will only want to select all of the characters between slash 5 and 6.

Answer 1

CLR functions are more efficient in handling strings than T-SQL. Here is some info to get you started on writing a CLR user defined function.
http://msdn.microsoft.com/en-us/library/ms189876.aspx
http://www.mssqltips.com/tip.asp?tip=1344
I think you should create the function that has 3 parameters:
the value you are searching
the delimiter (in your case: /)
The instance you are looking for (in your case: 5)
Then you split on the delimiter (into an array). Then return the 5th item in the array (index 4)
Here is a t-sql solution, but I really believe that a CLR solution would be better.
DECLARE #RRR varchar(500)
SELECT #RRR = '/abc/123/gyh/tgf/345/6yh/5er'
DECLARE
#index INT,
#INSTANCES INT
SELECT
#index = 1,
#INSTANCES = 5
WHILE (#INSTANCES > 1) BEGIN
SELECT #index = CHARINDEX('/', #RRR, #index + 1)
SET #INSTANCES = #INSTANCES - 1
END
SELECT SUBSTRING(#RRR, #index + 1, CHARINDEX('/', #RRR, #index + 1) - #index - 1)

Answer 2

SELECT SUBSTRING(myfield,
/* 5-th slash */
CHARINDEX('/', myfield,
CHARINDEX('/', myfield,
CHARINDEX('/', myfield,
CHARINDEX('/', myfield,
CHARINDEX('/', myfield) + 1) + 1) + 1) + 1)
+ 1,
/* 6-th slash */
CHARINDEX('/', myfield,
CHARINDEX('/', myfield,
CHARINDEX('/', myfield,
CHARINDEX('/', myfield,
CHARINDEX('/', myfield,
CHARINDEX('/', myfield) + 1) + 1) + 1) + 1) + 1)
-
/* 5-th slash again */
CHARINDEX('/', myfield,
CHARINDEX('/', myfield,
CHARINDEX('/', myfield,
CHARINDEX('/', myfield,
CHARINDEX('/', myfield) + 1) + 1) + 1) + 1)
- 1)
FROM myTable
WHERE ...
This will work, but it's far from elegant. If possible, select the complete field and filter out the required value on the client side (using a more powerful programming language than T-SQL). As you can see, T-SQL was not designed to do this kind of stuff.
(Edit: I know the following does not apply to your situation but I'll keep it as a word of advise for others who read this:)
In fact, relational databases are not designed to work with string-separated lists of values at all, so an even better solution would be to split that field into separate fields in your table (or into a subtable, if the number of entries varies).

Answer 3

Maybe... SELECT FROM `table` WHERE `field` LIKE '%/345/%'