SQL Server的日期计算

[size=large]a. 一个月的第一天 
SELECT DATEADD(mm, DATEDIFF(mm,0,getdate()), 0) 
b. 本周的星期一 
SELECT DATEADD(wk, DATEDIFF(wk,0,getdate()), 0) 
c. 一年的第一天 
SELECT DATEADD(yy, DATEDIFF(yy,0,getdate()), 0) 
d. 季度的第一天 
SELECT DATEADD(qq, DATEDIFF(qq,0,getdate()), 0) 
e. 上个月的最后一天 
SELECT dateadd(ms,-3,DATEADD(mm, DATEDIFF(mm,0,getdate()), 0)) 
f. 去年的最后一天 
SELECT dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate()), 0)) 
g. 本月的最后一天 
SELECT dateadd(ms,-3,DATEADD(mm, DATEDIFF(m,0,getdate())+1, 0)) 
h. 本月的第一个星期一 
select DATEADD(wk, DATEDIFF(wk,0, 
dateadd(dd,6-datepart(day,getdate()),getdate()) 
), 0) 
i. 本年的最后一天 
SELECT dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0))。 
获取表结构[把 'sysobjects' 替换 成 'tablename' 即可] 

SELECT CASE IsNull(I.name, '') 
When '' Then '' 
Else '*' 
End as IsPK, 
Object_Name(A.id) as t_name, 
A.name as c_name, 
IsNull(SubString(M.text, 1, 254), '') as pbc_init, 
T.name as F_DataType, 
CASE IsNull(TYPEPROPERTY(T.name, 'Scale'), '') 
WHEN '' Then Cast(A.prec as varchar) 
ELSE Cast(A.prec as varchar) + ',' + Cast(A.scale as varchar) 
END as F_Scale, 
A.isnullable as F_isNullAble 
FROM Syscolumns as A 
JOIN Systypes as T 
ON (A.xType = T.xUserType AND A.Id = Object_id('sysobjects') ) 
LEFT JOIN ( SysIndexes as I 
JOIN Syscolumns as A1 
ON ( I.id = A1.id and A1.id = object_id('sysobjects') and (I.status & 0x800) = 0x800 AND A1.colid <= I.keycnt) ) 
ON ( A.id = I.id AND A.name = index_col('sysobjects', I.indid, A1.colid) ) 
LEFT JOIN SysComments as M 
ON ( M.id = A.cdefault and ObjectProperty(A.cdefault, 'IsConstraint') = 1 ) 
ORDER BY A.Colid ASC [/size]