sql prefix with numbers - sql

Question

In my select I have multiple dates in one rows, divided by comma.
Main select:
SELECT DISTINCT p.IDVazniZaznam,
stuff(
(
SELECT ','+ CONVERT(VARCHAR,DatumCasZacatku, 22) FROM HVZHlavicka_Prestavka WHERE IDVazniZaznam = p.IDVazniZaznam FOR XML PATH('')
),1,1,'') As DatumCasZacatku,
stuff(
(
SELECT ','+ CONVERT(VARCHAR,DatumCasUkonceni, 22) FROM HVZHlavicka_Prestavka WHERE IDVazniZaznam = p.IDVazniZaznam FOR XML PATH('')
),1,1,'') AS DatumCasUkonceni
FROM (SELECT DISTINCT IDVazniZaznam, DatumCasUkonceni, DatumCasZacatku FROM HVZHlavicka_Prestavka ) p
Like this:
12/04/19 7:45:00 AM,12/04/19 8:00:02 AM
What I need to do is something like that:
1: 12/04/19 7:45:00 AM, 2: 12/04/19 8:00:02 AM
Im not sure if its called prefix, but I think it is. I do not want to put it manually, but I wanna generate it automatically. First date will be number 1, second date number 2 etc.
Its that even possible in SQL?

Answer 1

You can use logic from the below code-
DECLARE #text VARCHAR(MAX) = '12/04/19 7:45:00 AM,12/04/19 8:00:02 AM'
DECLARE #remaining_text VARCHAR(MAX) = #text
DECLARE #new_text VARCHAR(MAX) = ''
DECLARE #CommaIndex INT
DECLARE #Count INT = 1
SET #CommaIndex = CHARINDEX(',',#remaining_text,0)
IF #CommaIndex = 0
BEGIN
SET #new_text = '1: ' + #text
END
ELSE
BEGIN
WHILE #CommaIndex > 0
BEGIN
SET #new_text = #new_text+ ' '+CAST(#Count AS VARCHAR)+': ' + LEFT(#remaining_text,CHARINDEX(',',#remaining_text,0))
SET #remaining_text = RIGHT(#remaining_text,LEN(#remaining_text)-CHARINDEX(',',#remaining_text,0))
SET #CommaIndex = CHARINDEX(',',#remaining_text,0)
SET #Count = #Count + 1
END
END
IF CHARINDEX(',',#text,0) > 0
BEGIN
SET #new_text = #new_text + ' '+CAST(#Count AS VARCHAR)+': ' + #remaining_text
END
SELECT #new_text,#remaining_text
Output is-
1: 12/04/19 7:45:00 AM, 2: 12/04/19 8:00:02 AM

Answer 2

You can use STRING_AGG(), ROW_NUMBER() OVER (ORDER BY ..), STRING_SPLIT() and CONCAT() functions together ( STRING_AGG() works for SQL Server 2017+ ).
In the first step we're splitting the string by comma delimiters in the subquery, and then concatenating those substrings through use of STRING_AGG() :
DECLARE #DatumCasUkonceni NVARCHAR(1000) = '12/04/19 7:45:00 AM,12/04/19 8:00:02 AM';
SELECT STRING_AGG(q.str, ',' ) as "Result"
FROM
(
SELECT CONCAT( ROW_NUMBER() OVER (ORDER BY #DatumCasUkonceni), ' : ',
value ) as str
FROM STRING_SPLIT(#DatumCasUkonceni, ',')
) q
Demo

Answer 3

If STRING_AGG is available to your version of MS Sql Server (2017+), then something like this should do the job.
SELECT IDVazniZaznam
, STRING_AGG(CONCAT(rn,': ',DtStrCasZacatku),', ') AS DatumCasZacatku
, STRING_AGG(CONCAT(rn,': ',DtStrUkonceni),', ') AS DatumCasUkonceni
FROM
(
SELECT DISTINCT IDVazniZaznam
, CONVERT(VARCHAR,DatumCasZacatku, 22) AS DtStrCasZacatku
, CONVERT(VARCHAR,DatumCasUkonceni,22) AS DtStrUkonceni
, ROW_NUMBER() OVER (PARTITION BY IDVazniZaznam ORDER BY DatumCasZacatku, DatumCasUkonceni) AS rn
FROM HVZHlavicka_Prestavka
) q
GROUP BY IDVazniZaznam;
And this will also work in MS Sql Server 2012
WITH CTE AS
(
SELECT DISTINCT IDVazniZaznam
, DatumCasZacatku
, DatumCasUkonceni
, ROW_NUMBER() OVER (PARTITION BY IDVazniZaznam ORDER BY DatumCasUkonceni, DatumCasZacatku) AS rn
FROM HVZHlavicka_Prestavka
)
SELECT q.IDVazniZaznam
, STUFF(a1.DatumCasZacatku,1,2,'') AS DatumCasZacatku
, STUFF(a2.DatumCasUkonceni,1,2,'') AS DatumCasUkonceni
FROM
(
SELECT IDVazniZaznam
FROM CTE
GROUP BY IDVazniZaznam
) AS q
OUTER APPLY
(
SELECT CONCAT(', ',rn,': ', CONVERT(VARCHAR,DatumCasZacatku, 22))
FROM CTE c
WHERE c.IDVazniZaznam = q.IDVazniZaznam
FOR XML PATH ('')
) a1(DatumCasZacatku)
OUTER APPLY
(
SELECT CONCAT(', ',rn,': ', CONVERT(VARCHAR,DatumCasUkonceni,22))
FROM CTE c
WHERE c.IDVazniZaznam = q.IDVazniZaznam
FOR XML PATH ('')
) a2(DatumCasUkonceni);
Test for both on db<>fiddle here