通过GROUP，HAVING，recency等查询SQL

Question

我的'call_logs'表具有字段：id，phone_number，call_dialed_time，is_success。 （如果对电话号码的呼叫失败，则我们输入记录并稍后尝试再次呼叫）

对于尚未成功拨打的每个电话号码，我想获取最近的phone_number和call_dialed_time失败。

如何查询？

Answer 1

试试这个。

select distinct phone_number ,call_dialed_time from call_logs where phone_number not in(
select phone_number from call_logs group by phone_number having count(is_success) >0 
) order by call_dialed_time 

Answer 2

试试这个

select t1.* from call_logs as t1 inner join 
(
select 
phone_number, max(call_dialed_time) as call_dialed_time from call_logs 
where is_success=0 
group by phone_number 
) as t2 on t1.phone_number=t2.phone_number and t1.call_dialed_time=t2.call_dialed_time