update table with values in related records - sql

Question

I have a table which must be with next structure:
╔════╦═══════╦════╦═════╗
║ id ║ a ║ c ║ b ║
╠════╬═══════╬════╬═════╣
║ 55 ║ 56;57 ║ ║ P25 ║
║ 56 ║ ║ 56 ║ 25 ║
║ 57 ║ ║ 57 ║ 25 ║
╚════╩═══════╩════╩═════╝
where:
1) record with id=55 is a parent record and
2) records with id=56, id=57 (listed in a column and separated with semicolon) are child records
At first table is next
╔════╦═══════╦════╦═════╗
║ id ║ a ║ c ║ b ║
╠════╬═══════╬════╬═════╣
║ 55 ║ 56;57 ║ ║ ║
║ 56 ║ ║ 56 ║ ║
║ 57 ║ ║ 57 ║ ║
╚════╩═══════╩════╩═════╝
so I must to update table such as first table
For this purpose I created next CTE
with My_CTE(PId, a, c, b, newC, inde) as
(
select
ST.PID, ST.a, ST.c, ST.b, res.C,
ind = case
when ST.a != ''
then (dense_rank() over(order by ST.a))
end
from STable as ST
outer APPLY
fnSplit(ST.a) as res
where (not(ST.a = '') or not(ST.c = ''))
)
UPDATE STable
Set b =
cte.inde
From STable as st
Join My_CTE as cte on st.PID = cte.PId;
GO
As a result I have table with next values
╔════╦═══════╦════╦═════╗
║ id ║ a ║ c ║ b ║
╠════╬═══════╬════╬═════╣
║ 55 ║ 56;57 ║ ║ 25 ║
║ 56 ║ ║ 56 ║ ║
║ 57 ║ ║ 57 ║ ║
╚════╩═══════╩════╩═════╝
So I need to set values in column b for children records.
Maybe it could be established in select statement of MyCTE?
Help please

Answer 1

I am not entirely sure if I understand your request correctly so apologies if I have misunderstood.
So you have already managed to get the result set to here
╔════╦═══════╦════╦═════╗
║ id ║ a ║ c ║ b ║
╠════╬═══════╬════╬═════╣
║ 55 ║ 56;57 ║ ║ 25 ║
║ 56 ║ ║ 56 ║ ║
║ 57 ║ ║ 57 ║ ║
╚════╩═══════╩════╩═════╝
Now you want this to look like this
╔════╦═══════╦════╦═════╗
║ id ║ a ║ c ║ b ║
╠════╬═══════╬════╬═════╣
║ 55 ║ 56;57 ║ ║ P25 ║
║ 56 ║ ║ 56 ║ 25 ║
║ 57 ║ ║ 57 ║ 25 ║
╚════╩═══════╩════╩═════╝
Please see if this script works for you.
IF OBJECT_ID(N'tempdb..#temp')>0
DROP TABLE #temp
IF OBJECT_ID(N'tempdb..#temp1')>0
DROP TABLE #temp1
CREATE TABLE #temp (id int, a varchar(100),c varchar(100),b varchar(100))
INSERT INTO #temp VALUES ('55','56;57',' ','25')
INSERT INTO #temp VALUES ('56',' ','56',' ')
INSERT INTO #temp VALUES ('57',' ','57',' ')
SELECT * FROM #temp t
SELECT y.id, fn.string AS a,y.b
INTO #temp1
FROM #temp AS y
CROSS APPLY dbo.fnParseStringTSQL(y.a, ';') AS fn
--SELECT * FROM #temp1
UPDATE t
SET t.b=CASE WHEN CHARINDEX(';',t.a)>0 THEN 'P'+t.b ELSE t1.b END
FROM #temp t
LEFT JOIN #temp1 t1
ON t.id = t1.a
--DROP TABLE #temp
SELECT * FROM #temp t
IF OBJECT_ID(N'tempdb..#temp')>0
DROP TABLE #temp
IF OBJECT_ID(N'tempdb..#temp1')>0
DROP TABLE #temp1
Function borrowed from this link
CREATE FUNCTION [dbo].[fnParseStringTSQL]
(
#string NVARCHAR(MAX),
#separator NCHAR(1)
)
RETURNS #parsedString TABLE (string NVARCHAR(MAX))
AS
BEGIN
DECLARE #position INT
SET #position = 1
SET #string = #string + #separator
WHILE CHARINDEX(#separator, #string, #position) <> 0
BEGIN
INSERT INTO #parsedString
SELECT SUBSTRING(
#string,
#position,
CHARINDEX(#separator, #string, #position) - #position
)
SET #position = CHARINDEX(#separator, #string, #position) + 1
END
RETURN
END

Answer 2

This is really not an ideal data structure, but the following will do it...
CREATE TABLE #STable
(
id int primary key clustered
, a varchar(500)
, c varchar(500)
, b varchar(500)
)
INSERT INTO #STable
(id, a, c, b)
VALUES (55, '56;57', '', '25')
, (56, '', '56', '')
, (57, '', '57', '')
/* >>>>> Get all parents <<<<< */
CREATE TABLE #folks
(
sno int identity(1,1)
, id int
, a varchar(500)
)
CREATE TABLE #family
(
parent int
, child int
)
INSERT INTO #folks
(id, a)
SELECT id, a
FROM #STable
WHERE a <> ''
DECLARE #NID int
, #XID int
, #parent int
, #Children varchar(500)
, #Child int
SELECT #NID = MIN(sno), #XID = MAX(sno)
FROM #folks
/* >>>>> Loop to figure out the children <<<<< */
WHILE #NID <= #XID
BEGIN
SELECT #parent = id, #Children = a
FROM #folks
WHERE sno = #NID
WHILE LEN(#Children) > 0
BEGIN
IF CHARINDEX(';', #Children) > 0
BEGIN
SET #Child = CAST(LEFT(#Children, CHARINDEX(';', #Children) -1) as int)
SET #Children = RIGHT(#Children, LEN(#Children) - CHARINDEX(';', #Children))
INSERT INTO #family
(parent, child)
VALUES (#parent, #Child)
END
ELSE
BEGIN
SET #Child = CAST(#Children AS INT)
SET #Children = ''
INSERT INTO #family
(parent, child)
VALUES (#parent, #Child)
END
END
SET #NID = #NID + 1
END
/* >>>>> Update <<<<< */
UPDATE c
SET b = p.b
FROM #family f
INNER JOIN #STable p
on f.parent = p.id
INNER JOIN #STable c
on f.child = c.id
SELECT *
FROM #STable
DROP TABLE #STable
DROP TABLE #folks
DROP TABLE #family