Please start any new threads on our new
site at https://forums.sqlteam.com. We've got lots of great SQL Server
experts to answer whatever question you can come up with.
| Author |
Topic |
|
amos
Starting Member
5 Posts |
 Posted - 2009-10-15 : 14:01:29
|
| hello everyone,i found this on the web, it returns the first day of last week:SELECT DATEADD(wk,DATEDIFF(wk,6,GETDATE()-7),6)i cant understand how it works so tried to separate the function: * GETDATE()-7 = returns today - 7 days* DATEDIFF(wk,6,GETDATE()-7) = returns 5726, why? what is this number? why does it means how many weeks are from 6 until today - 7 days? * DATEADD(wk,DATEDIFF(wk,6,GETDATE()-7),6) = add 5726 weeks to 6, why? how does it works?can someone explain me?thanks all. |
|
|
TG
Master Smack Fu Yak Hacker
6065 Posts |
Posted - 2009-10-15 : 14:10:26
|
| It's magic :)no, not really - see if this helps solve a missing part of the puzzle. the "6" is implicitly converted to datetime. 0 represents 1/1/1900. 6 represents dateadd(day, 6, 0)which works out to: 1/7/1900. that day was a Sunday.Be One with the OptimizerTG |
 |
|
|
amos
Starting Member
5 Posts |
Posted - 2009-10-15 : 16:12:20
|
| thanks for the help,one more question:DATEDIFF(wk,6,GETDATE()-7) = returns 5726. what is this number? why does it means how many weeks are from 6 until today - 7 days? thanks a lot. |
|
|
|
TG
Master Smack Fu Yak Hacker
6065 Posts |
Posted - 2009-10-15 : 16:29:30
|
| >>what is this number?there were 5726 weeks between 1/7/1900 and seven days ago.Be One with the OptimizerTG |
|
|
|
|
|
|
|
|
help with date function