如何使用 group by 选项生成行号答案

【问题标题】：How To use generate row number with group by option如何使用 group by 选项生成行号
【发布时间】：2017-08-11 10:14:02
【问题描述】：

输入表 DEDUPE

SOURCE  Legacy_vendor   Vendor  Condition application   Condition type  Doc type    
MX_PRISMA_PDN   9215217 1012473 EF                   ZNE1             ZMRO  
MX_PRISMA_PDN   9215217 1012473 EF                   ZNE1             ZNB   
MX_PRISMA_PDN   9215217 1012473 EF                   ZNE1             ZSRM

输出应该是这样的

SOURCE  Legacy_vendor   Vendor  Condition application   Condition type  Doc type    
MX_PRISMA_PDN   9215217 1012473 EF                   ZNE1      ZMRO,ZNB,ZSRM

【问题讨论】：

您使用的是什么 DBMS？
•关系数据库
Oracle、MySQL、PostgreSQL 等？
您需要告诉我们您使用的是哪个 DBMS？后格雷斯？甲骨文？
我正在使用 MYSQL

标签： sql string-aggregation

【解决方案1】：

假设 SQL Server：您可以使用 XML 和 Stuff 来做到这一点

SELECT DISTINCT SOURCE,Legacy_vendor,Vendor,[Condition application],[Condition type],STUFF((SELECT ','+[Doc type]

            FROM Table1 T1
             WHERE T1.SOURCE=T2.SOURCE
                AND T1.Legacy_vendor=T2.Legacy_vendor
                AND T1.Vendor=T2.Vendor
             FOR XML PATH('')
            ), 1, 1, '')
             AS [Doc type]
FROM Table1 T2

Demo

【讨论】：

【解决方案2】：

对于 SQL Server

select source, legacy_vendor, vendor, condition_application, condition_type,
doctype = 
 STUFF((    SELECT ' '+ SUB.doctype AS [text()]  
FROM DEDUPE SUB  
WHERE  sub.source = main.source and  sub.legacy_vendor = main.legacy_vendor and
       sub.vendor = main.vendor and sub.condition_application= main.condition_application and sub.condition_type = main.condition_type
FOR XML PATH('') 
), 1, 1,'')  
 from DEDUPE main
 group by source, legacy_vendor, vendor, condition, condition_type

我使用 STUFF 将所有文档类型加入 1 列中

【讨论】：

这是用于哪个 dbms？

【解决方案3】：

您没有告诉我们您的 DBMS。

对于 PostgreSQL，您可以使用 string_agg()

select source, 
       Legacy_vendor, 
       Vendor, 
       "Condition application"
       "Condition type"
        string_agg("Doc type", ',') as doc_type
from the_table
group by source, 
       Legacy_vendor, 
       Vendor, 
       "Condition application"
       "Condition type"

【讨论】：

【解决方案4】：

BEGIN TRAN
CREATE TABLE  #DEDUPE (SOURCE NVARCHAR(50),Legacy_vendor BIGINT,Vendor BIGINT ,[Condition application]  NVARCHAR(10),[Condition type] NVARCHAR(20),[Doc type]  NVARCHAR(20))


INSERT INTO #DEDUPE
SELECT 'MX_PRISMA_PDN' ,9215217, 1012473,'EF','ZNE1','ZMRO' UNION ALL
SELECT 'MX_PRISMA_PDN', 9215217, 1012473,'EF','ZNE1','ZNB' UNION ALL
SELECT 'MX_PRISMA_PDN', 9215217, 1012473,'EF','ZNE1','ZNB' 


    SELECT
    C.SOURCE,
    C.Legacy_vendor,C.Vendor,C.[Condition application],C.[Condition type],
        STUFF((  
                SELECT  ', ' +  CONVERT(Nvarchar,CP.[Doc type])
                FROM  
                #DEDUPE CP
                WHERE
                    C.SOURCE = CP.SOURCE
                    FOR XML PATH('')), 1, 2, '') [Doc type]
    FROM
    #DEDUPE C 
    GROUP BY    C.SOURCE,
    C.Legacy_vendor,C.Vendor,C.[Condition application],C.[Condition type]

DROP TABLE #DEDUPE
ROLLBACK TRAN

【讨论】：