Dynamically update column value with replacement for some pattern - sql

Question

I have my table with Column MailText which has values like
1. <strong>abc</strong>:<description1> <strong>bcd</strong>:<description2>
2. <strong>efg</strong>:<description3> <strong>hgl</strong>:<description7>
Upon update I want values like
1. <strong>abc</strong>:<abc> <strong>bcd</strong>:<bcd>
2. <strong>efg</strong>:<efg> <strong>hgl</strong>:<hgl>
Please help with dynamic replacement that it would update all string within <strong> tag to <description>. <strong> tag may contain any values.

Answer 1

CREATE FUNCTION GetString
(
#s NVARCHAR(MAX)
)
RETURNS NVARCHAR(MAX)
AS
BEGIN
DECLARE #trav NVARCHAR(2000) = #s,
#length INT,
#count INT = 1,
#startIndex INT = 0,
#endIndex INT = 0,
#replaceStartIndex INT = 0,
#repalceEndIndex INT = 0,
#replaceword NVARCHAR(2000),
#newWord NVARCHAR(2000)
SELECT #length = LEN(#Trav)
WHILE ((#count + #startIndex) <= #length)
BEGIN
SET #startIndex = CHARINDEX('<strong>', #trav, #startIndex) + LEN('<strong>')
IF (#startIndex > 8)
BEGIN
SET #endIndex = CHARINDEX('</strong>', #trav, #startIndex)
SET #newWord = SUBSTRING(#trav, #startIndex, (#endIndex - #startIndex))
SET #replaceStartIndex = CHARINDEX(':', #trav, #startIndex) + 2
SET #repalceEndIndex = CHARINDEX('>', #trav, #replaceStartIndex)
SET #replaceword = SUBSTRING(
#trav,
#replaceStartIndex,
(#repalceEndIndex - #replaceStartIndex)
)
--SELECT #replaceword as 'repword', #newWord as 'newword'
SET #trav = REPLACE (#trav, #replaceword, #newWord)
SET #count = #repalceEndIndex
END
ELSE
BEGIN
SET #count = #count + 1
END
END
RETURN #trav
END
GO
IF OBJECT_ID('tempdb..#table') IS NOT NULL
DROP TABLE #table
CREATE TABLE #table
(
string VARCHAR(1000)
)
INSERT INTO #table
SELECT
'1. <strong>abc</strong>:<description1> <strong>bcd</strong>:<description2>'
INSERT INTO #table
SELECT
'2. <strong>efg</strong>:<description3> <strong>hgl</strong>:<description7>'
UPDATE #table
SET string = [dbo].[GetString](#table.string)
SELECT *
FROM #table