Solved

T-SQL string manipulation without using Loop?  T-SQL support regular expressions?  (SQL Server 2005)

Posted on 2010-11-11
2
514 Views
Last Modified: 2012-06-27
I'm trying to write an efficient SQL statement to do the following string replacement on a single column in a table (see blow):

FIND THIS: 0. DISC *:
REPLACE WITH: <strong>DISC *:</strong>

where * is an integer from 1 to 10.

In other words, I wish to remove the "0." in front of the word "DISC" and make the actual disc number bold.

(There are other rows in the table that don't start with text "0. DISC" at all.)

There will be multiple occurrences of the search string in each row.

Any ideas for how to pull this off efficiently?  My loop (below) runs just fine but is slow as molasses.  Plus, it just feels "wrong" to use a loop! ;)   I wish T-SQL nativity supported regular expressions.

I may end up taking an entirely different approach to solving this problem but before I do I was hoping someone had a quick solution in mind that could help me.

sample INPUT tracks row:

0. DISC 1: text here 0. DISC 2: text here 0. DISC 3: text here 1. some other data untouched 2. yet another row untouched

sample RESULT tracks row:

<strong>DISC 1:</strong> text here <strong>DISC 2:</strong> text here <strong>DISC 3:</strong> text here 1. some other data untouched 2. yet another row untouched
create table CompactDiscs (
    id int,
    tracks varchar(4000)   
)

Inefficient Version:
declare @counter int
set @counter = 1
while @counter <= 10
begin
	print 'The counter is ' + cast(@counter as char)

	update CompactDiscs set tracks=REPLACE(tracks,'0. DISC '+cast(@counter as varchar)+':','<strong>DISC '+cast(@counter as varchar)+'</strong>');
	set @counter = @counter + 1
end

Open in new window

0
Comment
Question by:ZuZuPetals
2 Comments
 
LVL 32

Accepted Solution

by:
bhess1 earned 500 total points
ID: 34114364
The difficulty with this one was the possibility of the 10 value.  Here is one solution I came up with:


CREATE TABLE #t (
	id int IDENTITY,
	tracks varchar(50)
	)
INSERT INTO #t(tracks) VALUES ('ewin 0. DISC 1: asdoab')
INSERT INTO #t(tracks) VALUES ('0. DISC 2:')
INSERT INTO #t(tracks) VALUES ('0. DISC 3:a sdfabsuif')
INSERT INTO #t(tracks) VALUES ('0. DISC 4:')
INSERT INTO #t(tracks) VALUES ('asnwr 0. DISC 5:')
INSERT INTO #t(tracks) VALUES ('0. DISC 6:')
INSERT INTO #t(tracks) VALUES ('0. DISC 7:')
INSERT INTO #t(tracks) VALUES ('0. DISC 8:')
INSERT INTO #t(tracks) VALUES ('0. DISC 9:')
INSERT INTO #t(tracks) VALUES ('0. DISC 10:')
INSERT INTO #t(tracks) VALUES ('0. DISC 191:');

WITH tfx AS (
SELECT 
	id,
	PATINDEX('%0. DISC [123456789]:%', tracks) o9,
	PATINDEX('%0. DISC 10:%', tracks) o10
FROM #t
WHERE tracks LIKE '%0. DISC [123456789]:%'
	OR tracks LIKE '%0. DISC 10:%'
)
UPDATE #t
SET tracks = 
	CASE 
		WHEN o9 = 0
			THEN
				CASE
					WHEN o10 = 1
						THEN ''
					ELSE LEFT(tracks, o10-1)
				END + '<strong>' + SUBSTRING(tracks, o10+3, 8) + '</strong>' + SUBSTRING(tracks, o10+11, LEN(tracks))
		ELSE 
			CASE
				WHEN o9 = 1
					THEN ''
				ELSE LEFT(tracks, o9-1)
			END + '<strong>' + SUBSTRING(tracks, o9+3, 7) + '</strong>' + SUBSTRING(tracks, o9+10, LEN(tracks))
	END
FROM #t 
INNER JOIN tfx
	ON tfx.id = #t.id

Open in new window

0
 
LVL 2

Author Closing Comment

by:ZuZuPetals
ID: 34122599
I never thought of using PatIndex().  Thanks for putting so much work into this!!!
0

Featured Post

Windows Server 2016: All you need to know

Learn about Hyper-V features that increase functionality and usability of Microsoft Windows Server 2016. Also, throughout this eBook, you’ll find some basic PowerShell examples that will help you leverage the scripts in your environments!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In SQL Server, when rows are selected from a table, does it retrieve data in the order in which it is inserted?  Many believe this is the case. Let us try to examine for ourselves with an example. To get started, use the following script, wh…
This article explains how to reset the password of the sa account on a Microsoft SQL Server.  The steps in this article work in SQL 2005, 2008, 2008 R2, 2012, 2014 and 2016.
Learn how to match and substitute tagged data using PHP regular expressions. Demonstrated on Windows 7, but also applies to other operating systems. Demonstrated technique applies to PHP (all versions) and Firefox, but very similar techniques will w…
Explain concepts important to validation of email addresses with regular expressions. Applies to most languages/tools that uses regular expressions. Consider email address RFCs: Look at HTML5 form input element (with type=email) regex pattern: T…

773 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question