如何根据条件从db获取时间

Question

我有一个表格，其值为

             Table_hello
date                            col2
2012-01-31 23:01:01             a
2012-06-2  12:01:01             b
2012-06-3  20:01:01             c

现在我要选择日期

1. 如果是3天之前的日子或更少
2. 如果是24小时之前的小时或更少
3. 如果是60分钟或更短的话，只需几分钟
4. 如果是60秒或更短
，则以秒为单位
5. 如果是在3天或更长时间之前以简单格式

输出

for row1 2012-01-31 23:01:01 
for row2 1 day ago 
for row3 1 hour ago 

UPDATE 我的SQL查询

  select case 
            when TIMESTAMPDIFF(SECOND, `date`,current_timestamp) <= 60 
            then concat(TIMESTAMPDIFF(SECOND, `date`,current_timestamp), ' seconds')
            when TIMESTAMPDIFF(DAY, `date`,current_timestamp) <= 3 
            then concat(TIMESTAMPDIFF(DAY, `date`,current_timestamp), ' days')end
            when TIMESTAMPDIFF(HOUR, `date`,current_timestamp) <= 60 
            then concat(TIMESTAMPDIFF(HOUR, `date`,current_timestamp), ' hours')
            when TIMESTAMPDIFF(MINUTE, `date`,current_timestamp) <= 60 
            then concat(TIMESTAMPDIFF(MINUTE, `date`,current_timestamp), ' minutes')

from table_hello

唯一的问题是我无法在sql中使用break和default，例如c ++中的switch case

Answer 1

使用timestampdiff功能和CASE：

select case 
        when TIMESTAMPDIFF(SECOND, `date`,current_timestamp) <= 60 
        then concat(TIMESTAMPDIFF(SECOND, `date`,current_timestamp), ' seconds')
        when TIMESTAMPDIFF(DAY, `date`,current_timestamp) <= 3 
        and TIMESTAMPDIFF(DAY, `date`,current_timestamp) >= 1 
        ...
       end as time_diff 
from Table_hello
where TIMESTAMPDIFF(DAY, `time`,current_timestamp) >= 3