根据手工输入身份证号码得到年龄存储过程

create proc IdToAgeProc
  @Idcard varchar(20),
  @Age int output
 as 
 begin
  declare @birthDateStr varchar(10)
  declare @yearStr varchar(10)
  declare @monthStr varchar(10)
  declare @dayStr varchar(10)
  declare @nowdateStr varchar(20)
  declare @AgeStr varchar(10)
set @birthDateStr =SUBSTRING(@Idcard,7,8)
set @nowdateStr = CONVERT(varchar(10),GETDATE(),112)
set @AgeStr=DATEDIFF(YEAR,@birthDateStr,@nowdateStr)
if(SUBSTRING(@birthDateStr,5,4) <= SUBSTRING(@nowdateStr,5,4))
       begin 
            --Cast()将字符转化为数字函数        
            set @Age = CAST(@AgeStr as int) 
       end
    else             
      begin
           set @Age = CAST(@AgeStr as int)-1
      end
    --输出计算后的返回结果-- 
    select @Age as 年龄
end
drop proc IdToAgeProc

--测试1：出生日期已过当前日期的---
declare @Idcard varchar(20)