SQL-转换为日期

Question

I have a numeric column in SQL which I need to convert to a date. The field is currently coming into the database as: "20181226.00000" .

I only need to the characters before the " . " . So i did a SUBSTRING - CHARINDEX looking for anything before the " . " . I then did a cast as NVARCHAR .

Now I'm getting 20181226 but I want this date field to populate like: "MM/DD/YYYY" .

My current SQL is:

CONVERT(VARCHAR(10),SUBSTRING(CAST('MYFIELD' AS NVARCHAR(50)) ,0, CHARINDEX('.', 'MYFIELD' , 0)),101)

Answer 1

只需将101更改为103

CONVERT(VARCHAR(10),SUBSTRING(CAST('MYFIELD' AS NVARCHAR(50)) ,0, CHARINDEX('.', 'MYFIELD' , 0)),101)

Answer 2

The easiest way is to convert it to what it actually is, a date , and then back to a varchar using the right style.

SELECT convert(varchar(max), convert(date, substring(convert(varchar(max), nmuloc), 1, charindex('.', convert(varchar(max), nmuloc)) - 1)), 101)
       FROM elbat;

I wasn't sure if it's a number or a string. If it's a string you don't need the convert(varchar(max), nmuloc) s.

However a side note: You should not store dates as numbers or strings. Use an appropriate data type like date .

Answer 3

Or you could achieve it like this.

declare @v_value numeric(18,5)=20181226.00000

SELECT SUBSTRING(CAST(CAST(@v_value AS INT) AS VARCHAR),5,2)+'/'+SUBSTRING(CAST(CAST(@v_value AS INT) AS VARCHAR),7,2)+'/'+SUBSTRING(CAST(CAST(@v_value AS INT) AS VARCHAR),1,4) as V_OUTPUT

--Output
/*
V_OUTPUT
------------------
12/26/2018
*/

Best Regards,

Will

Answer 4

First we have convert to varchar and then Date format

SELECT  CONVERT(varchar, CAST(CAST('20181206.00000' as VARCHAR(8)) AS DATE), 103); dd/mm/yyyy

SELECT  CONVERT(varchar, CAST(CAST('20181206.00000' as VARCHAR(8)) AS DATE), 101); mm/dd/yyyy