转换存储为文本的多种日期格式

Question

I have a column that is a date column that is stored as text. This has three formats in it.

1. dd mmm yyyy
2. MM/dd/yyyy
3. yyyy-mm-dd

I need to convert all these to one format. Im hoping 112 (yyyymmdd)

can anyone help as I keep getting an out of range error.

I have got it to return this correctly

CONVERT(varchar(10), ISNULL(CAST(cf3.FieldValue as date),CAST('01/01/1900' as date)),101)

But I cant seem to then convert to yyyymmdd format without the range error.

Answer 1

Input:

01 Jan 1900
12/5/2013
2013-12-10

Query:

SELECT CONVERT(VARCHAR, CONVERT(DATE, TestColumn), 112)
FROM tblTestTable 

Output:

19000101
20131205
20131210

Using SQL Server 2008 R2

Answer 2

You can use combination of STR_TO_DATE with DATE_FORMAT to achieve desired results.

SELECT
IFNULL(
  DATE_FORMAT(STR_TO_DATE(COL_NAME, '%d %b %Y'), '%Y%m%d'), 
  IFNULL(
    DATE_FORMAT(STR_TO_DATE(COL_NAME, '%d-%m-%Y'), '%Y%m%d'),
    DATE_FORMAT(STR_TO_DATE(COL_NAME, '%Y-%m-%d'), '%Y%m%d')
  )
) FROM TABLE_NAME;

STR_TO_DATE will convert the string into a datetime datatype and then DATE_FORMAT will convert datetime into the desired format( '%Y%m%d' -> 'yyyymmdd' ).

Answer 3

declare @mydate datetime = '2017-03-20'

select RIGHT('0' + CAST(DATEPART(DD,@mydate) as nvarchar(max)),2) + ' ' + UPPER(CAST(DATENAME(month,@mydate) AS VARCHAR(3))) + ' ' + CAST(DATEPART(YEAR, @mydate) as nvarchar(MAX)) as 'dd mmm yyyy',
RIGHT('0' + CAST(DATEPART(DD,@mydate) as nvarchar(max)),2) + '/' + RIGHT('0' + CAST(DATEPART(MONTH, @mydate) as nvarchar(Max)),2) + '/' + CAST(DATEPART(YEAR, @mydate) as nvarchar(MAX)) as 'dd/mm/yyyy',
CAST(DATEPART(YYYY,@mydate) as nvarchar(max)) + '-' + RIGHT('0' + CAST(DATEPART(MONTH, @mydate) as nvarchar(Max)),2) + '-' + RIGHT('0' + CAST(DATEPART(DD, @mydate) as nvarchar(MAX)),2) as 'yyyy-mm-dd'

You can manually get the corresponding dateparts of the date and perform the formatting yourself. (if format needed is not readily available)