您可以按应用程序分组，然后对事件使用条件计数。

SELECT
APP,
COUNT(CASE WHEN EVENT = 'clk' THEN 1 END) AS clk,
COUNT(CASE WHEN EVENT = 'imp' THEN 1 END) AS imp,
COUNT(CASE WHEN EVENT = 'req' THEN 1 END) AS req
FROM yourtable
GROUP BY APP
ORDER BY APP;

这里是sql fiddle示例

您可以尝试使用聚合函数条件

SELECT APP,
       SUM(CASE WHEN EVENT ='clk' THEN 1 ELSE 0 END) clk,
       SUM(CASE WHEN EVENT ='imp' THEN 1 ELSE 0 END) imp,
       SUM(CASE WHEN EVENT ='req' THEN 1 ELSE 0 END) req
FROM T
GROUP BY APP

mysql提供了条件聚合的简写，因此您可以：

select app, 
       sum(EVENT = 'clk') as clk,
       sum(EVENT = 'imp') as imp,
       sum(EVENT = 'req') as req
from table t
group by app;

这把小提琴显示它在工作