打开的单柱SQL SELECT结果列表成一行

Question

我怎样才能使语句：

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回报

value1, value2, value3 (where value1 is for USA, value2 for BRA, value3 for CHN) 

我得到的最好的，到目前为止是与单个列所有值从数据库中提取出来。

Answer 1

你可以做到以下几点：

Select a.column1,b.column2,c.column3 from 
(SELECT column1 FROM db WHERE country ='USA' and commodity='pork') as a, 
(SELECT column1 FROM db WHERE country ='BRA' and commodity='pork') as b, 
(SELECT column1 FROM db WHERE country ='CHN' and commodity='pork') as c 

Answer 2

你可能寻找的GROUP_CONCAT（）函数：

http://www.sqlite.org/lang_aggfunc.html

Answer 3

我相信你正在寻找工作台旋转。我回答了一个类似的问题here但是我不熟悉SQLLite，因此它可能是相似的。

Answer 4

喜欢的东西：

SELECT column1 as value1 FROM db WHERE country='USA' and commodity='pork' 
UNION 
SELECT column1 as value2 FROM db WHERE country='BRA' and commodity='pork' 
UNION 
SELECT column1 as value3 FROM db WHERE country='CHN' and commodity='pork' 

Answer 5

使用SQL支点。这会帮助你。

Answer 6

这是一个演示文稿问题。 更容易让Python的处理：

import sqlite3 
conn = sqlite3.connect('/path/to/your.db') 
curs = conn.cursor() 
results = curs.execute("""SELECT column1 
          FROM db 
          WHERE country in ('USA','BRA','CHN') 
          AND commodity='pork';""").fetchall() 
', '.join(str(result[0]) for result in results) 

Answer 7

你想是这样的：

select 
    base.commodity 
,USA_db.column1 as Commodity_USA 
,BRA_db.column1 as Commodity_BRA 
,CHN_db.column1 as Commodity_CHA 
from (select 'pork' as commodity) as base 
left join db as USA_db on base.commodity = USA_db.commodity and USA_db.country = 'USA' 
left join db as BRA_db on base.commodity = BRA_db.commodity and BRA_db.country = 'BRA' 
left join db as CHN_db on base.commodity = CHN_db.commodity and CHN_db.country = 'USA' 
; 

输出将是：

commodity Commodity_USA Commodity_BRA Commodity_CHA 
---------- ------------- ------------- ------------- 
pork  USA-pork  BRA-pork  USA-pork 

Answer 8

select max(case country 
       when 'USA' then column1 
       else null 
       end) USA, 
      max(case country 
       when 'BRA' then column1 
       else null 
       end) BRA, 
      max(case country 
       when 'CHN' then column1 
       else null 
       end) CHN 
    FROM db 
    WHERE country in ('USA','BRA','CHN') 
    and commodity='pork' 

一个单传过来的数据（单个查询），并且你聚合了三行，换句话说什么都没有。

Answer 9

这应该工作（在MySQL测试）

SELECT GROUP_CONCAT(column1) FROM db WHERE country in ('USA','BRA','CHN') and commodity='pork' 

我的测试是这样的（在MySQL）

SELECT GROUP_CONCAT(uid) FROM pages where title in ('Home','Footer','home') 

结果：

1,3,10 

这是正确的..