送高分，datediff问题！！！

Question

？？
datediff(ss,'2004-8-21 00:00:00,convert(datetime,left()+'-'+..........'))
--〉
datediff(ss,'2004-8-21 00:00:00',convert(datetime,left()+'-'+ '..........'))

Answer 1

请参考如下：
select CONVERT(varchar(10), getDate(),120) --不要时间2002-1-1
select convert(char(8),getdate(),112) ----20020101
select convert(char(8),getdate(),108)  ---06:05:05

Answer 2

比如：select datediff(ss,'2004-8-21 00:00:00',convert(datetime,left('2004-8-21',6)+'-'+ '22'))结果：
            
----------- 
      86400 （所影响的行数为 1 行）

Answer 3

convert(datetime,left()+'-'+..........')的结果是日期型的，不用加单引号
你的问题是前面的少写了一个单引号

Answer 4

多谢各位，可是select * from tbilllog where datediff(ss,'2004-08-01 00:00:00',convert(datetime,'.......'))>0 却无法得到相应的记录，而数据库中明明是有这些记录的，而且没有报语法错，只是出来空集，如果查select * from tbilllog where datediff(ss,'2004-08-01 00:00:00',convert(datetime,'.......'))<0的部分，到也能查处来，很奇怪，为什么了？convert的结果和datediff的结果都能单独弄出来，都是正确地！！！多谢

Answer 5

select datediff(day,convert(datetime,'2004-8-21 00:00:00'),convert(datetime,left('2004-8-21',6)+'-'+ '22'))
这样返回的是天，楼主的程序返回的是秒

Answer 6

用cast
datediff(ss,convert(datetime,'2004-1-23 00:00:00'),cast(sj as datetime ))>0

Answer 7

其实就是要从一个表中搜出固定时间段的集合，很简单，却.....贴出原句，大家给看看：
select callerNo, calleeNo, Starttime, Answertime, Releasetime from tBillLog where datediff(ss, '2004-8-29 19:00:00', convert(datetime,(left(Releasetime,4)+'-'+(right(left(Releasetime,6),2))+'-'+(right(left(Releasetime,8),2))+' '+(right(left(Releasetime,10),2))+':'+(right(left(Releasetime,12),2))+':'+(right(left(Releasetime,14),2)))))>0 and datediff(ss,convert(datetime,(left(Releasetime,4)+'-'+(right(left(Releasetime,6),2))+'-'+(right(left(Releasetime,8),2))+' '+(right(left(Releasetime,10),2))+':'+(right(left(Releasetime,12),2))+':'+(right(left(Releasetime,14),2)))), '2004-8-29 20:00:00')>0多谢

Answer 8

楼主，我建议你先将Releasetime这个字段处理成你需要的格式放在一个临时字段里，然后再做比较。
或者将前面的'2004-8-29 19:00:00'转换为字符串来比较字符串的大小
convert(varchar,'2004-8-29 19:00:00')>convertconvert(varchar,(left(Releasetime,4)+'-'+(right(left(Releasetime,6),2))+'-'+(right(left(Releasetime,8),2))+' '+(right(left(Releasetime,10),2))+':'+(right(left(Releasetime,12),2))+':'+(right(left(Releasetime,14),2))))