移調列結果在結果集中行

Question

我從這樣的查詢

Continent Country 
------- ------- 
Asia Japan 
Asia Russia 
Asia India 
Europe Britain 
Europe France 

一個結果

select continent,country from tablexxx 

我想導致格式

Continent Country 
------- ------- 
Asia Japan,Russia,India 
Europe Britain,France 

我聽說支點表。但似乎很難，我... 與查詢任何幫助，請:)

這是我在SQL Server最終的解決方案，它的工作原理... :)

SELECT  continents, Countries = replace 
          ((SELECT Countries AS [data()] 
           FROM tblXXX 
           WHERE continents = a.continents 
           ORDER BY continents FOR xml path('')), ' ', ',') 
FROM  tblXXXa 
WHERE  continents IS NOT NULL 
GROUP BY continents 

Answer 1

如果你使用MySQL，你需要使用GROUP_CONCAT

例如：

SELECT continent, GROUP_CONCAT(county ORDER BY country) as Countries 
FROM tablexxx 
GROUP BY continent 
ORDER BY continent 

鏈接
http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html#function_group-concat

Answer 2

可以使用COALESCE函數在這個例子中建立從行的逗號分隔的列表，如：

DECLARE @EmployeeList varchar(100) 

SELECT @EmployeeList = COALESCE(@EmployeeList + ', ', '') + 
    CAST(Emp_UniqueID AS varchar(5)) 
FROM SalesCallsEmployees 
WHERE SalCal_UniqueID = 1 

SELECT @EmployeeList