Question

这是GAMES表中的摘录：

ID  WUSER       BUSER
1   ddyer       bdot
2   ddyer       ronaldinho
3   bluedog     ronaldinho
4   ronaldinho  bluedog
5   bluedog     ronaldinho
6   ddyer       bobc
7   bobc        ddyer

该表是来自boardpace.net网站的数据库，其中人们玩棋盘游戏。在数据库中，wuser和buser用于白人和黑人玩家，id是游戏。现在我想知道发挥最多的球员。所以我为白人玩家做这件事：

 SELECT wuser, count(wuser) 
 FROM game 
 GROUP BY wuser 
 ORDER BY count(wuser) DESC;

结果是：

wuser    count(wuser)
Dumbot   75926
guest    22541
image13  1594
DrRaven  1460
Eucalyx  1147
Loizz    963

然后我必须为黑人球员做同样的事情：

 SELECT buser, count(buser) 
 FROM game 
 GROUP BY buser 
 ORDER BY count(buser) DESC;

buser    count(buser)
Dumbot   59489
guest    29324
Eucalyx  1007
image13  756
DrRaven  746
Loizz    715
alexis   660

我可以像下面一样手动加总，但是如何从单个SQL语句中获取结果：

user     count(as both buser and wuser)
Dumbot   135412
guest    51865
image13  2350
DrRaven  2206

我只想知道每个玩家的游戏总数，我不感兴趣他们是白色还是黑色。

Answer 1

当你为每个用户获得大量行时，你最好在UNION之前计算COUNT并添加另一个聚合步骤：

SELECT usr, sum(cnt)
FROM
 (
   SELECT wuser as usr, count(*) as cnt
   FROM game 
   GROUP BY wuser

   UNION ALL

   SELECT buser, count(*) 
   FROM game 
   GROUP BY buser
 ) AS dt
 GROUP BY usr
 ORDER BY sum(cnt) DESC;

Answer 2

您可以使用UNION取消对桌子的取消操作。然后只需GROUP BY用户名和COUNT：

SELECT usr, COUNT(usr)
FROM (
   SELECT WUSER AS usr 
   FROM GAMES

   UNION ALL

   SELECT BUSER AS usr 
   FROM GAMES ) u
GROUP BY usr
ORDER BY COUNT(usr) DESC

SQL Fiddle Demo

Sqlite：从两个相关列中获取模态/模式

2 个答案: