SQL基础：sql通过日期判断年龄函数的示例代码

CREATE FUNCTION [dbo].[GetAge]
(
@BirthDay nvarchar(20) –生日
)
RETURNS varchar(20)
AS
BEGIN
if(@BirthDay is NUlL or @BirthDay=”)
return ”;
— Declare the return variable here
DECLARE @age varchar(20)
DECLARE @years int
DECLARE @months int
DECLARE @days int
— Add the T-SQL statements to compute the return value here
set @age = ”

set @years = year(GETDATE()) – year(@birthday)
set @months = month(GETDATE()) – month(@birthday)
if day(@birthday)<=day(GETDATE())
set @days = day(GETDATE()) – day(@birthday)
else
begin
set @months = @months – 1
if MONTH(@birthday) in (1,3,5,7,8,10,12)
set @days = 31-day(@birthday)+day(GETDATE())
else if MONTH(@birthday) in (4,6,9,11)
set @days = 30-day(@birthday)+day(GETDATE())
else if MONTH(@birthday) = 2
if (year(@birthday)%4 = 0 and year(@birthday)%100 <> 0) or year(@birthday)%400 = 0
set @days = 29-day(@birthday)+day(GETDATE())
else
set @days = 28-day(@birthday)+day(GETDATE())
end
if @months < 0
begin
set @years = @years – 1
set @months = @months + 12
end
if @years = 0 and @months = 0
begin
return convert(varchar,@days+1) + ‘天’
end
if @years > 0
set @age = cast(@years as varchar(5)) + ‘岁’
if @years < 3 and @months > 0 and @years>-1
begin
set @age = @age + cast(@months as varchar(5)) + ‘月’
end
if @years<0
set @age=”
RETURN @age
END