SQL Server：将多行合并为一行

Question

我有一个这样的 SQL 查询；

SELECT * 
FROM Jira.customfieldvalue
WHERE CUSTOMFIELD = 12534
AND ISSUE = 19602

结果就是这样；

我想要的是；显示在一行（单元格）中，将所有 STRINGVALUE 组合在一起，并用逗号分隔。像这样；

SELECT --some process with STRINGVALUE--
FROM Jira.customfieldvalue
WHERE CUSTOMFIELD = 12534
AND ISSUE = 19602

Araç Listesi (C2, K1 vb.Belgeler; yoksa Ruhsat Fotokopileri), Min. 5
araç plakası için İnternet Sorgusu, Son 3 Yıla Ait Onaylı Yıl Sonu
Bilanço + Gelir Tablosu, Son Yıl (Yıl Sonuna ait) Detay Mizanı, İçinde
Bulunduğumuz Yıla ait Ara Dönem Geçici Vergi Beyannamesi, Bayi Yorum
E-Maili, Proforma Fatura

我该怎么做？

Answer 1

这是一个老问题，但在 Microsoft SQL Server 2017 发布后，您现在可以使用 STRING_AGG() 函数，这很像 MySQL 中的 GROUP_CONCAT 函数。

STRING_AGG (Transact-SQL) Documentation

示例

USE AdventureWorks2016
GO
SELECT STRING_AGG (CONVERT(NVARCHAR(max),FirstName), ',') AS csv 
FROM Person.Person; 

返回

Syed,Catherine,Kim,Kim,Kim,Hazem

Answer 2

declare @maxColumnCount int=0;
 declare @Query varchar(max)='';
 declare @DynamicColumnName nvarchar(MAX)='';

-- table type variable that store all values of column row no
 DECLARE @TotalRows TABLE( row_count int)
 INSERT INTO @TotalRows (row_count)
 SELECT (ROW_NUMBER() OVER(PARTITION BY InvoiceNo order by InvoiceNo Desc)) as row_no FROM tblExportPartProforma

-- Get the MAX value from @TotalRows table
 set @maxColumnCount= (select max(row_count) from @TotalRows)
 
-- loop to create Dynamic max/case and store it into local variable 
 DECLARE @cnt INT = 1;
 WHILE @cnt <= @maxColumnCount
 BEGIN
   set @DynamicColumnName= @DynamicColumnName + ', Max(case when row_no= '+cast(@cnt as varchar)+' then InvoiceType end )as InvoiceType'+cast(@cnt as varchar)+''
      set @DynamicColumnName= @DynamicColumnName + ', Max(case when row_no= '+cast(@cnt as varchar)+' then BankRefno end )as BankRefno'+cast(@cnt as varchar)+''
            set @DynamicColumnName= @DynamicColumnName + ', Max(case when row_no= '+cast(@cnt as varchar)+' then AmountReceived end )as AmountReceived'+cast(@cnt as varchar)+''

      set @DynamicColumnName= @DynamicColumnName + ', Max(case when row_no= '+cast(@cnt as varchar)+' then AmountReceivedDate end )as AmountReceivedDate'+cast(@cnt as varchar)+''


   SET @cnt = @cnt + 1;
END;

-- Create dynamic CTE and store it into local variable @query 
  set @Query='
     with CTE_tbl as
     (
       SELECT InvoiceNo,InvoiceType,BankRefno,AmountReceived,AmountReceivedDate,
       ROW_NUMBER() OVER(PARTITION BY InvoiceNo order by InvoiceNo Desc) as row_no
       FROM tblExportPartProforma
      )
  select
     InvoiceNo
     '+@DynamicColumnName+'
     FROM CTE_tbl
     group By InvoiceNo'

-- Execute the Query
 execute (@Query)

Answer 3

CREATE VIEW  [dbo].[ret_vwSalariedForReport]
AS
     WITH temp1 AS (SELECT
     salaried.*,
     operationalUnits.Title as OperationalUnitTitle
FROM
    ret_vwSalaried salaried LEFT JOIN
    prs_operationalUnitFeatures operationalUnitFeatures on salaried.[Guid] = operationalUnitFeatures.[FeatureGuid] LEFT JOIN 
    prs_operationalUnits operationalUnits ON operationalUnits.id = operationalUnitFeatures.OperationalUnitID 
    ), 
temp2 AS (SELECT
    t2.*,
    STUFF ((SELECT ' - ' + t1.OperationalUnitTitle
        FROM
            temp1 t1 
        WHERE t1.[ID] = t2.[ID]  
        For XML PATH('')), 2, 2, '') OperationalUnitTitles from temp1 t2) 
SELECT 
    [Guid],
    ID,
    Title,
    PersonnelNo,
    FirstName,
    LastName,
    FullName,
    Active,
    SSN,
    DeathDate,
    SalariedType,
    OperationalUnitTitles
FROM 
    temp2
GROUP BY 
    [Guid],
    ID,
    Title,
    PersonnelNo,
    FirstName,
    LastName,
    FullName,
    Active,
    SSN,
    DeathDate,
    SalariedType,
    OperationalUnitTitles

Answer 4

我相信对于支持listagg功能的数据库，你可以这样做：

select id, issue, customfield, parentkey, listagg(stingvalue, ',') within group (order by id)
from jira.customfieldvalue
where customfield = 12534 and issue = 19602
group by id, issue, customfield, parentkey

Answer 5

使用 MySQL 内置函数 group_concat() 将是获得所需结果的不错选择。语法将是 -

SELECT group_concat(STRINGVALUE) 
FROM Jira.customfieldvalue
WHERE CUSTOMFIELD = 12534
AND ISSUE = 19602

在执行上述命令之前，请确保增加 group_concat_max_len 的大小，否则整个输出可能不适合该单元格。

要设置 group_concat_max_len 的值，请执行以下命令-

SET group_concat_max_len = 50000;

您可以相应地更改值 50000，根据需要将其增加到更高的值。

Answer 6

有几种方法。

如果您只想返回合并后的字符串值，这是一种快速简便的方法

DECLARE @combinedString VARCHAR(MAX)
SELECT @combinedString = COALESCE(@combinedString + ', ', '') + stringvalue
FROM jira.customfieldValue
WHERE customfield = 12534
    AND ISSUE = 19602

SELECT @combinedString as StringValue 

这将返回您的组合字符串。

您也可以尝试其中一种 XML 方法，例如

SELECT DISTINCT Issue, Customfield, StringValues
FROM Jira.customfieldvalue v1
CROSS APPLY ( SELECT StringValues + ',' 
              FROM jira.customfieldvalue v2
              WHERE v2.Customfield = v1.Customfield 
                  AND v2.Issue = v1.issue 
              ORDER BY ID 
                  FOR XML PATH('') )  D ( StringValues )
WHERE customfield = 12534
    AND ISSUE = 19602

Answer 7

在 MySql 中有一个方便的方法，叫做 GROUP_CONCAT。不存在 SQL Server 的等效项，但您可以使用 SQLCLR 编写自己的。幸运的是，someone 已经为你做到了。

然后您的查询变成这样（顺便说一句，这是一个更好的语法）：

SELECT CUSTOMFIELD, ISSUE, dbo.GROUP_CONCAT(STRINGVALUE)
FROM Jira.customfieldvalue
WHERE CUSTOMFIELD = 12534 AND ISSUE = 19602
GROUP BY CUSTOMFIELD, ISSUE

但请注意，此方法适用于组内最多 100 行。除此之外，您将遇到主要的性能问题。 SQLCLR 聚合必须对任何中间结果进行序列化，这很快就会堆积很多工作。请记住这一点！

有趣的是，FOR XML 并没有遇到同样的问题，而是使用了可怕的语法。

Answer 8

你可以通过如下方式组合 For XML Path 和 STUFF 来实现：

SELECT (STUFF((
        SELECT ', ' + StringValue
        FROM Jira.customfieldvalue
        WHERE CUSTOMFIELD = 12534
        AND ISSUE = 19602
        FOR XML PATH('')
        ), 1, 2, '')
    ) AS StringValue