[英]How to concatenate strings in SQL Server, and sort/ order by a different column?
我在 SQL Server 中看到了很多連接字符串的例子,但如果他們擔心排序,它總是由被連接的列組成。 我需要根據不同字段中的數據對值進行排序。
示例表:
ClassID | StudentName | SortOrder
-----------------------------
A |James |1
A |Janice |3
A |Leonard |2
B |Luke |2
B |Leia |1
B |Artoo |3
我想得到的結果是:
ClassID |StudentName
--------------------------------
A |James, Leonard, Janice
B |Leia, Luke, Artoo
如何在 SQL Server 2016 中做到這一點? (我很期待 2017 年的 STRING_AGG,但我們還沒有……)
謝謝!
干得好:
SELECT
s1.ClassID
, STUFF((SELECT
',' + s2.StudentName
FROM dbo.Student AS s2
WHERE s1.classID = s2.ClassID
ORDER BY s2.SortOrder
FOR XML PATH('')), 1, 1, '') AS StudentNames
FROM dbo.Student AS s1
GROUP BY s1.ClassID
這里查詢
IF OBJECT_ID('tempdb..#Temp') IS NOT NULL DROP TABLE #Temp;
CREATE TABLE #Temp(ClassId varchar(10),studName varchar(100),SortOrder int)
INSERT INTO #Temp(ClassId , studName, SortOrder)
SELECT 'A','James',1 UNION ALL
SELECT 'A','Janice',3UNION ALL
SELECT 'A','Leonard',2 UNION ALL
SELECT 'B','Luke',2 UNION ALL
SELECT 'B','Leia',1 UNION ALL
SELECT 'B','Artoo',3
-- select * from #Temp
select
distinct
stuff((
select ',' + u.studName
from #Temp u
where u.studName = studName and U.ClassId = L.ClassId
order by u.SortOrder
for xml path('')
),1,1,'') as userlist,ClassId
from #Temp L
group by ClassId
MS SQL Server 2017 架構設置:
CREATE TABLE MyTable(ClassID varchar(255),StudentName varchar(255),SortOrder int)
INSERT INTO MyTable(ClassID,StudentName,SortOrder)VALUES('A','James',1),('A','Janice',3),('A','Leonard',2),
('B','Luke',2),('B','Lela',1),('B','Artoo',3)
查詢 1 :
SELECT
t.ClassID
, STUFF((SELECT
',' + t1.StudentName
FROM MyTable t1
WHERE t.classID = t1.ClassID
ORDER BY t1.SortOrder
FOR XML PATH('')), 1, 1, '') AS StudentNamesConcat
FROM MyTable AS t
GROUP BY t.ClassID
結果:
| ClassID | StudentNamesConcat |
|---------|----------------------|
| A | James,Leonard,Janice |
| B | Lela,Luke,Artoo |
您也可以嘗試使用 PIVOT。 這將支持更舊版本的 SQL 服務器。 唯一的限制:您應該知道最大 SortOrder 值。 下面的代碼適用於任何 ClassID 的 SortOrder <=20
SELECT ClassID, ISNULL([1],'') +ISNULL(', '+[2],'')+ISNULL(', '+[3],'')+ISNULL(', '+
[4],'')+ISNULL(', '+[5],'')+ISNULL(', '+[6],'')+ISNULL(', '+[7],'')+ISNULL(', '+
[8],'')+ISNULL(', '+[9],'')+ISNULL(', '+[10],'')+ISNULL(', '+[11],'')+ISNULL(', '+
[12],'')+ISNULL(', '+[13],'')+ISNULL(', '+[14],'')+ISNULL(', '+[15],'')+ISNULL(', '+
[16],'')+ISNULL(', '+[17],'')+ISNULL(', '+[18],'')+ISNULL(', '+[19],'')+ISNULL(', '+
[20],'') AS StudentName
FROM
(SELECT SortOrder,ClassID,StudentName
FROM [Table1] A
) AS SourceTable
PIVOT
(
MAX(StudentName)
FOR SortOrder IN ([1],[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18],[19],[20])
) AS PivotTable
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