查询查找差异并仅显示差异小于零的记录

Question

我在使用以下查询在MySql中查找某些记录时遇到问题

select 
dletterdate,
days,
date_add(dletterdate,interval days day) as added ,
now() as todaysdate, datediff(now(),date_add(dletterdate,interval days day)) as difference  
from mandereports

实际上我想只显示差异小于零的记录。这是输出的屏幕截图：

Answer 1

您可以使用WHERE子句。

select 
    dletterdate,
    days,
    date_add(dletterdate,interval days day) as added ,
    now() as todaysdate, datediff(now(),date_add(dletterdate,interval days day)) as difference  
    from mandereports
    where difference < 0

希望这有帮助