如何根据出生日期和 getDate() 计算年龄（以年为单位）

小编典典

如何根据出生日期和 getDate() 计算年龄（以年为单位）

all

我有一张表格，列出了人们的出生日期（目前是 nvarchar(25)）

如何将其转换为日期，然后以年为单位计算他们的年龄？

我的数据如下

ID    Name   DOB
1     John   1992-01-09 00:00:00
2     Sally  1959-05-20 00:00:00

我想看看：

ID    Name   AGE  DOB
1     John   17   1992-01-09 00:00:00
2     Sally  50   1959-05-20 00:00:00

阅读 67

2022-06-25

共1个答案

小编典典

闰年/闰日和以下方法存在问题，请参阅下面的更新：

尝试这个：
DECLARE @dob  datetime
SET @dob='1992-01-09 00:00:00'

SELECT DATEDIFF(hour,@dob,GETDATE())/8766.0 AS AgeYearsDecimal
    ,CONVERT(int,ROUND(DATEDIFF(hour,@dob,GETDATE())/8766.0,0)) AS
AgeYearsIntRound
,DATEDIFF(hour,@dob,GETDATE())/8766 AS AgeYearsIntTrunc

输出：
AgeYearsDecimal                         AgeYearsIntRound
AgeYearsIntTrunc
--------------------------------------- ----------------
17.767054                               18               17

(1 row(s) affected)

更新这里有一些更准确的方法：

多年来最好的方法

DECLARE @Now  datetime, @Dob datetime
SELECT   @Now='1990-05-05', @Dob='1980-05-05'  --results in 10
--SELECT @Now='1990-05-04', @Dob='1980-05-05'  --results in  9
--SELECT @Now='1989-05-06', @Dob='1980-05-05'  --results in  9
--SELECT @Now='1990-05-06', @Dob='1980-05-05'  --results in 10
--SELECT @Now='1990-12-06', @Dob='1980-05-05'  --results in 10
--SELECT @Now='1991-05-04', @Dob='1980-05-05'  --results in 10

SELECT
    (CONVERT(int,CONVERT(char(8),@Now,112))-CONVERT(char(8),@Dob,112))/10000 AS AgeIntYears

您可以将上面的内容更改10000为10000.0并获得小数，但它不会像下面的方法那样准确。

多年来最好的十进制方法

DECLARE @Now  datetime, @Dob datetime
SELECT   @Now='1990-05-05', @Dob='1980-05-05' --results in 10.000000000000
--SELECT @Now='1990-05-04', @Dob='1980-05-05' --results in  9.997260273973
--SELECT @Now='1989-05-06', @Dob='1980-05-05' --results in  9.002739726027
--SELECT @Now='1990-05-06', @Dob='1980-05-05' --results in 10.002739726027
--SELECT @Now='1990-12-06', @Dob='1980-05-05' --results in 10.589041095890
--SELECT @Now='1991-05-04', @Dob='1980-05-05' --results in 10.997260273973

SELECT 1.0* DateDiff(yy,@Dob,@Now) 
    +CASE 
         WHEN @Now >= DATEFROMPARTS(DATEPART(yyyy,@Now),DATEPART(m,@Dob),DATEPART(d,@Dob)) THEN  --birthday has happened for the @now year, so add some portion onto the year difference
           (  1.0   --force automatic conversions from int to decimal
              * DATEDIFF(day,DATEFROMPARTS(DATEPART(yyyy,@Now),DATEPART(m,@Dob),DATEPART(d,@Dob)),@Now) --number of days difference between the @Now year birthday and the @Now day
              / DATEDIFF(day,DATEFROMPARTS(DATEPART(yyyy,@Now),1,1),DATEFROMPARTS(DATEPART(yyyy,@Now)+1,1,1)) --number of days in the @Now year
           )
         ELSE  --birthday has not been reached for the last year, so remove some portion of the year difference
           -1 --remove this fractional difference onto the age
           * (  -1.0   --force automatic conversions from int to decimal
                * DATEDIFF(day,DATEFROMPARTS(DATEPART(yyyy,@Now),DATEPART(m,@Dob),DATEPART(d,@Dob)),@Now) --number of days difference between the @Now year birthday and the @Now day
                / DATEDIFF(day,DATEFROMPARTS(DATEPART(yyyy,@Now),1,1),DATEFROMPARTS(DATEPART(yyyy,@Now)+1,1,1)) --number of days in the @Now year
             )
     END AS AgeYearsDecimal

2022-06-25