SQL int转换为日期时间的字符串

Question

I have date in integers.

What is the cleanest way to convert integers to datetime?

I used this messy way:

CONVERT(DATETIME,  cast(source.Day as varchar(2)) + '/' + cast(source.Month as varchar(2)) + '/' + cast(source.Year as varchar(2)), 3),

Answer 1

You can use DATEFROMPARTS function:

SELECT DATEFROMPARTS ( 2010, 12, 31 ) AS Result;

Note, it is only available in 2012+ editions.

Answer 2

Here is how you can do that

   Declare @date date, 
        @year INT = 2014,
        @Month INT = 10,
        @DateDay INT = 12,
        @parseDate char(20)

select @date = CONVERT(date, 
                CAST( Cast(@Year as char(4))
                         + Cast(@Month as char(2)) +
                          cast(@DateDay as char(2))  AS CHAR(12)), 112)
select @date

Note : I am not handling NULL cases.

Answer 3

尝试这个：

select CONVERT (datetime,convert(char(8),yourvalue))

Answer 4

Working from RTs solution this might work

CREATE TABLE DATA(yr int, mth int, dy int);
INSERT INTO DATA
VALUES (2014,10,15);

SELECT
      CONVERT (DATETIME,
                CONVERT(char(4), yr) + 
                CONVERT(char(2), mth) + 
                CONVERT(char(2), dy)
       ) as Result
FROM DATA

This is still a bit messy and assumes a 4 digit year integer.

SQL Fiddle here: http://sqlfiddle.com/#!6/cbf62/2