mysql - 简单的 MySQL 问题

Question

好的，我有一个带有Wor的列L来指定输赢。我想统计所有的输赢，得到一个胜率。

SELECT banner_name, count(win_loss) as wins 
FROM drop_log 
where win_loss = 'W' 
group by banner_name

这给了我所有的球队以及他们有多少胜利。我将如何调整它以使另一列用于损失，另一列用于比率。MySQL 似乎具有与 SQL Server 2008 不同的语法规则。

Answer 1

SELECT banner_name, SUM(IF(win_loss = "W", 1, 0)) AS wins,
    SUM(IF(win_loss = "L", 1, 0)) AS losses
FROM drop_log
GROUP BY banner_name

You may also be able to get the percentage in this way, but it's easy to divide after the selection too.

It would also be better to use a boolean (0 or 1) to designate a win or loss, but this would work in pretty much the same way.

EDIT: It would actually work to simply use SUM(win_loss = 'letter') as this will return 1 or 0 already.

Answer 2

这将为您提供所需的所有 3 个值。

SELECT banner_name, wins, total-wins AS losses, wins/total AS win_ratio
FROM (select banner_name, SUM(win_losses = 'W') AS wins, COUNT(*) AS total
      FROM drop_log
      GROUP BY banner_name) w