一个时间条件查询语句问怎么写！！急

Question

语句如是：
SELECT UNIT_ID,SUM(BOROUGH_ADVICEASSISNUM)ADVICEASSISNUM,count(EXTEND_ID)EXTEND_ID,SUM(BOROUGH_ADVICESUBSIDY)ADVICESUBSIDY
FROM T_BYW_JZFF 
WHERE SALVATION_YEAR_MON=@SALVATION_YEARMON AND REVIEW_UNIT_ID="1" 
GROUP BY REVIEW_UNIT_IDSALVATION_YEAR_MON 是时间字段为字符型怎么样取到时间为当前系统时间的年月并做为条件进行查询
运行语句列SALVATION_YEAR_MON=200709

Answer 1

select convert(varchar(6),getdate(),112)

Answer 2

存储过程中经常用到的本周，本月，本年函数 
Dateadd(wk,datediff(wk,0,getdate()),-1)                              
Dateadd(wk,datediff(wk,0,getdate()),6) 
Dateadd(mm,datediff(mm,0,getdate()),0) 
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0))Dateadd(yy,datediff(yy,0,getdate()),0)
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0))