怎么根据出生年月（字符串）计算准确的年龄

declare @x varchar(10)

select @x='2012-2'

select rtrim(datediff(m,@x+'-01',getdate())/12)+'岁'
      +rtrim(datediff(m,@x+'-01',getdate())%12)+'月' 'age'

/*
age
----------------------------
2岁3月

(1 row(s) affected)
*/

declare @brithdate   varchar(20)
set @brithdate='1970-1'

select datediff(yy,@brithdate+'-01',getdate())


/*
 44
*/