Merge SQL Server, MySQL, and Oracle rows

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Merge multiple rows and one column of data into one row and one column of data

Http://topic.csdn.net/u/20090714/17/5FE6A0F7-CE78-4936-BE31-21D462236059.html

Merge data in MySQL and Oracle

Http://www.blogjava.net/rain1102/archive/2009/06/24/283867.html

SQL Server

-- Method 2 in sql2005
Create   Table TB (ID Int , Value Varchar ( 10 ))
Insert   Into TB Values ( 1 , ' AA ' )
Insert   Into TB Values ( 1 , ' Bb ' )
Insert   Into TB Values ( 2 , ' Aaa ' )
Insert   Into TB Values ( 2 , ' Bbb ' )
Insert   Into TB Values ( 2 , ' CCC ' )
Go

Select ID, [ Values ] = Stuff (( Select   ' , ' + [ Value ]   From TB t Where ID = TB. ID
For XML Path ( '' )), 1 , 1 , '' )
From TB
Group   By ID

/* 
ID values
-------------------------------
1 aa, BB
2 AAA, BBB, CCC

(2 row (s) affected)

*/ 

Drop TableTB

MySQL

Select Name, group_concat (email Order   By Email separator ",") As Email From Student Group   By Name

Oracle

If the above results are to be displayed in Oracle, it is more complicated. Because there is no row merging function in Oracle, you need to use sys_connect_by_path () for implementation,CodeAs follows:
Select Name, Ltrim (Sys_connect_by_path (email, ' , ' ), ' , ' ) Email From (
Select Name, email,
Row_number () Over (Partition By Name Order   By Email) Rn,
Count ( * ) Over (Partition By Name) CNT
From Student
) Where   Level   = CNT
Start With Rn =   1
Connect By Prior name = Name And Prior Rn +   1   = Rn