Question

select player.ActionTime from question_log log inner join player_question player 
where log.ActionType='96'

select player.ActionTime from question_log log inner join player_question player 
where log.ActionType='97'

如何在mysql语法中实现这一点？选择ActionType为96减去另一个为97的Actiontime。算术减去。

Answer 1

SELECT t96.ActionTime - t97.ActionTime
FROM
(
    select player.ActionTime 
    from question_log log 
    inner join player_question player 
    where log.ActionType='96'
) t96
CROSS JOIN
(
    select player.ActionTime 
    from question_log log 
    inner join player_question player 
    where log.ActionType='97'
) t97

请注意，您的两个查询之间似乎没有任何关联，因此我只能建议CROSS JOIN（笛卡尔积）。如果您有多行log.ActionType ='96'或log.ActionType = '97'，您将拥有许多结果行。

Answer 2

使用子查询：

SELECT player.ActionTime - (SELECT player.ActionTime from question_log log inner join     player_question player where log.ActionType='97' LIMIT 1)
from question_log log inner join player_question player where log.ActionType='96'

如何在两个选择之间使用mysql中的算术减去？

2 个答案: