AndroidHttpClient线程安全(Is AndroidHttpClient thread safe)

 这种情况很好，这是在SQL中完成的，而不是在应用程序代码中完成的。 这是在PostgreSQL中如何做到这一点。 （查询似乎在MySQL 5.6中没有修改就可以工作，这让我感到很惊讶。） 
 
create table test (
  test_id integer primary key,
  created_at timestamp not null default current_timestamp
  );

insert into test values 
(1, current_timestamp),
(2, current_timestamp - interval '1' day),
(3, current_timestamp - interval '10' day);
 
 使用CASE语句和简单的日期算法可以完成您想要的任何操作。 
 
select test_id,
       case current_date - cast(created_at as date)
           when 0 then 'Added today'
           when 1 then 'Added yesterday'
           else 'Added some time ago'
       end as when_added
from test
order by created_at desc, test_id asc

TEST_ID  WHEN_ADDED
--
1        Added today
2        Added yesterday
3        Added some time ago
 
 当您order by created_at desc ，您的数据会按显示顺序自然返回（不考虑您的应用程序可能需要的任何其他列），而在php中您只需要显示“when_added”列。 你不需要在php中进行任何操作。 

Odds are good that this is done in SQL, not in application code. Here's how to do that in PostgreSQL. (The query seems to work without modification in MySQL 5.6, which surprised me a little bit.)
 
create table test (
  test_id integer primary key,
  created_at timestamp not null default current_timestamp
  );

insert into test values 
(1, current_timestamp),
(2, current_timestamp - interval '1' day),
(3, current_timestamp - interval '10' day);
 
Use a CASE statement and simple date arithmetic to do pretty much anything you want.
 
select test_id,
       case current_date - cast(created_at as date)
           when 0 then 'Added today'
           when 1 then 'Added yesterday'
           else 'Added some time ago'
       end as when_added
from test
order by created_at desc, test_id asc

TEST_ID  WHEN_ADDED
--
1        Added today
2        Added yesterday
3        Added some time ago
 
When you order by created_at desc, your data is naturally returned in display order (not considering whatever other columns your application might need), and in php you just need to display that "when_added" column. You don't need to do any manipulation in php.