打開的單柱SQL SELECT結果列表成一行

Question

我怎樣才能使語句：

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回報

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

我得到的最好的，到目前爲止是與單個列所有值從數據庫中提取出來。

Answer 1

你可以做到以下幾點：

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

你可能尋找的GROUP_CONCAT（）函數：

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

Answer 3

我相信你正在尋找工作臺旋轉。我回答了一個類似的問題here但是我不熟悉SQLLite，因此它可能是相似的。

Answer 4

喜歡的東西：

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支點。這會幫助你。

Answer 6

這是一個演示文稿問題。 更容易讓Python的處理：

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

你想是這樣的：

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' 
; 

輸出將是：

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' 

一個單傳過來的數據（單個查詢），並且你聚合了三行，換句話說什麼都沒有。

Answer 9

這應該工作（在MySQL測試）

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

我的測試是這樣的（在MySQL）

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

結果：

1,3,10 

這是正確的..