concatenate row data of a column based on group - sql

Question

Thank you for anyone who is help. I am seeking help to create an sql script to do the following.
Have the following table
REF 1
REF 2
Ref 3
wt
91112
43111
14928-001
2
91112
43111
14928-002
5
91113
42555
14940-001
3
91112
43111
14928-003
4
91114
42556
14941-001
1
where the yield would be great like the following
REF 1
REF 2
REF 3
WT
91112
43111
14928-001/002/003
11
91113
42555
14940-001
3
91114
42556
14941-001
1
I stumped at how to get 14928-001|002|003 as a merged value
this is for T-SQL
Thank you,

Answer 1

If you were using SQL Server 2017 or later, you could use the STRING_AGG function. But since you are using SQL Server 2014, you have to use the FOR XML trick.
I have a solution, and it isn't elegant and there is most likely a better way to this, but here goes.
First, I set up a table variable and put your data in it. I then used a common table expression and some grouping to create an intermediate result:
Declare #Data TABLE(REF1 INT NOT NULL, REF2 INT NOT NULL, REF3 VARCHAR(20) NOT NULL, WT INT NOT NULL);
INSERT INTO #Data(REF1, REF2, REF3, WT)
VALUES (91112, 43111, '14928-001', 2),
(91112, 43111, '14928-002', 5),
(91113, 42555, '14940-001', 3),
(91112, 43111, '14928-003', 4),
(91114, 42556, '14941-001', 1);
;WITH Step1 AS
(
SELECT REF1, REF2, REF3,
LEFT(REF3, CHARINDEX('-', REF3) - 1) AS REF3_LEFT,
SUBSTRING(REF3, CHARINDEX('-', REF3) + 1, LEN(REF3) - CHARINDEX('-', REF3)) AS REF3_RIGHT,
WT
FROM #Data
)
SELECT p.REF1, p.REF2, p.REF3_LEFT,
(SELECT '/' + REF3_RIGHT FROM Step1 AS sub
WHERE p.REF1 = sub.REF1 AND p.REF2 = sub.REF2
ORDER BY sub.REF3_RIGHT
FOR XML PATH (''), TYPE).value('.','VARCHAR(MAX)') AS suffixes,
SUM(WT) AS WT
FROM Step1 AS p
GROUP BY REF1, REF2, REF3_LEFT
ORDER BY REF1, REF2;
The result of this look like the following:
REF1
REF2
REF3_LEFT
suffixes
WT
91112
43111
14928
/001/002/003
11
91113
42555
14940
/001
3
91114
42556
14941
/001
1
This is very close... all we need to do now is replace the leading / of suffixes with a - and the concatenate it to REF3_LEFT and we will have it. So I will make another common table expression from the first and get the result you have shown above:
Declare #Data TABLE(REF1 INT NOT NULL, REF2 INT NOT NULL, REF3 VARCHAR(20) NOT NULL, WT INT NOT NULL);
INSERT INTO #Data(REF1, REF2, REF3, WT)
VALUES (91112, 43111, '14928-001', 2),
(91112, 43111, '14928-002', 5),
(91113, 42555, '14940-001', 3),
(91112, 43111, '14928-003', 4),
(91114, 42556, '14941-001', 1);
;WITH Step1 AS
(
SELECT REF1, REF2, REF3,
LEFT(REF3, CHARINDEX('-', REF3) - 1) AS REF3_LEFT,
SUBSTRING(REF3, CHARINDEX('-', REF3) + 1, LEN(REF3) - CHARINDEX('-', REF3)) AS REF3_RIGHT,
WT
FROM #Data
), Step2 AS
(
SELECT p.REF1, p.REF2, p.REF3_LEFT,
(SELECT '/' + REF3_RIGHT FROM Step1 AS sub
WHERE p.REF1 = sub.REF1 AND p.REF2 = sub.REF2
ORDER BY sub.REF3_RIGHT
FOR XML PATH (''), TYPE).value('.','VARCHAR(MAX)') AS suffixes,
SUM(WT) AS WT
FROM Step1 AS p
GROUP BY REF1, REF2, REF3_LEFT
)
SELECT REF1, REF2, CONCAT(REF3_LEFT , '-', SUBSTRING(suffixes, 2, LEN(suffixes) -1)) AS REF3, WT
FROM Step2;
And this is the result:
REF1
REF2
REF3
WT
91112
43111
14928-001/002/003
11
91113
42555
14940-001
3
91114
42556
14941-001
1
There is the desired output you have shown. Obviously you do not need the table variable since you have the table and data, but it should be easy for you to replace #Data with the actual table name.