Question

table1
    - date1 datetime not null
    - date2 nvarchar null

我想知道这两个人的最新日期。

select date1, date2, 
(CASE WHEN date1 > CAST(date2 as DateTime) THEN date1 ELSE date2 END) as DateTime) as LatestDate
from table1

请注意，date2可以是null。在这种情况下，date1 win。

Answer 1

SELECT date1, date2,  
CASE 
  WHEN date1 > CAST(ISNULL(date2,'1900-01-01') as DateTime) THEN 
     date1 
  ELSE 
    CAST(date2 as DateTime) 
END  as LatestDate 
FROM table1

Answer 2

将CAST(date2 as DateTime)更改为CAST(isnull(date2,'01/01/1900') as DateTime)

Answer 3

这是一个非常好的解决方案，但我怀疑Nathan's solution更好。

http://p2p.wrox.com/oracle/6592-calculate-de-max-value-two-columns.html

sql - 获取两列的最新日期

3 个答案: