SQL server一行变多行，多行变一行

VIN码唯一，力洋ID多。 多行变1行

SELECT A.[VIN码], B.[力洋ID] FROM

(

  SELECT [VIN码], [力洋ID] = CONVERT(xml,'<root><v>' + REPLACE([力洋ID], ';', '</v><v>') + '</v></root>') FROM [tbl_VINdecode]

) A OUTER APPLY

(

  SELECT [力洋ID] = N.v.value('.', 'varchar(100)') FROM A.[力洋ID].nodes('/root/v') N(v)

) B

--多行合并为一行

R语言

方法一

https://stackoverflow.com/questions/22756372/collapse-text-by-group-in-data-frame

aggregate(df$text, list(df$group), paste, collapse="")

##  Group.1      x

## 1      a a1a2a3

## 2      b  b1b2

## 3      c c1c2c3

From <https://stackoverflow.com/questions/22756372/collapse-text-by-group-in-data-frame>

方法二

library(plyr)

ddply(df, .(group), summarize, text=paste(text, collapse=""))

##  group  text

## 1    a a1a2a3

## 2    b  b1b2

## 3    c c1c2c3

From <https://stackoverflow.com/questions/22756372/collapse-text-by-group-in-data-frame>