Converting float fields to date Time

Question

I have an application that stores datetimes into float fields, the data is formatted yyyymmddhhmmss or 20081122091030. I need to convert this data to a datetime data type so I can do datetime calculations (differences) for reporting purposes. It would be preferable to have the data formatted yyyy/mm/dd hh:mms. I have tried numerous methods with out success. As I understand it I need to CONVERT to a VARCHAR first.  I am new to TSQL & this one turning out to be a knotty problem so I would really appreciate anyone’s assistance,
SELECT (
  LEFT(CAST(IS_DUE_DATE AS VARCHAR(14)),8) + ' ' +
    SUBSTRING(CAST(IS_DUE_DATE AS VARCHAR(14)),9,2) + ':' +
    SUBSTRING(CAST(IS_DUE_DATE AS VARCHAR(14)),11,2) + ':' +
    SUBSTRING(CAST(IS_DUE_DATE AS VARCHAR(14)),13,2))
FROM  ISSUES
However when I try to Covert to DATETIME it all goes pear shaped.

Answer 1

Try this
Code Snippet
DECLARE @MyDate float
SET @MyDate = 20090922112143997
SELECT CONVERT(DATETIME,
LEFT(CAST(CAST(@MyDate as BigInt) as varchar(20)),8)+' '+
SUBSTRING(CAST(CAST(@MyDate as BigInt) as varchar(20)),9,2)+':'+
SUBSTRING(CAST(CAST(@MyDate as BigInt) as varchar(20)),11,2)+':'+
SUBSTRING(CAST(CAST(@MyDate as BigInt) as varchar(20)),13,2) + '.' +
SUBSTRING(CAST(CAST(@MyDate as BigInt) as varchar(20)),15,3)
Added using a temp table:
Code Snippet
CREATE TABLE #T
fdate float
go
INSERT INTO #T VALUES (20090922112143997)
INSERT INTO #T VALUES (20090921182143997)
INSERT INTO #T VALUES (20090921012323997)
SELECT CONVERT(DATETIME,
LEFT(CAST(CAST(fdate as BigInt) as varchar(20)),8)+' '+
SUBSTRING(CAST(CAST(fdate as BigInt) as varchar(20)),9,2)+':'+
SUBSTRING(CAST(CAST(fdate as BigInt) as varchar(20)),11,2)+':'+
SUBSTRING(CAST(CAST(fdate as BigInt) as varchar(20)),13,2) + '.' +
SUBSTRING(CAST(CAST(fdate as BigInt) as varchar(20)),15,3)
FROM #T
DROP TABLE #T