Question

我坚持做些什么。当他最早的日期与另一个领域匹配时，我怎么能找到某些东西的结果。说我需要知道谁买了苹果和橘子，但先买了一个苹果。

Cleint 1

DATE        Fruit
1st          Apple
2nd          Apple
3rd          Orange

客户2

DATE        Fruit
1st          Orange
2nd          Apple 
3rd          Orange

客户3

-(void) doTask1{
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
    //your code
    });
}

-(void) doTask2{
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
    //your code
    });
}

我只想得到客户2的结果。我已尝试过Min / Man和concat的变体。但我没有运气。谢谢。

Answer 1

这样的东西？

select Client
from t
group by Client
having min(case when Fruit = 'Apple'  then date else null end) 
     < min(case when Fruit = 'Orange' then date else null end)

最早的数据和匹配领域

1 个答案: