Based on the data Convert the datatype and make the wrong date as NULL

Question

Hi,
In the below scenario we are inserting some time related fields in Temp table.But its data type is varchar. Once data loading is finished in the temp table (Data is loading by source team SQOOP and they are unable to load if the source datatype is having
Date or datetime) we have to alter the column datatypes. somehow, some character data in inserted in date columns (look at into 3rd insert statement). while altering the table it is failing. Can we do any alternative for this (Means if any varchar data that
is non convertible to date can we make as null)
INSERT INTO ##TEMP_TEST
SELECT '2014-09-30','2017-10-06','Nov  6 2014  6:11AM','Nov  6 2014  6:11AM'
UNION SELECT '2014-09-29','2017-10-06','Nov  6 2014  6:11AM','Nov  6 2014  6:11AM'
UNION SELECT '2014-09-28','2017-10-06','Nov  6 2014  6:11AM','Nov  6 2014  6:11AM'
GO
INSERT INTO ##TEMP_TEST SELECT NULL,NULL,NULL,NULL 
GO
INSERT INTO ##TEMP_TEST SELECT 'A','B','C','D'
go
ALTER TABLE ##TEMP_TEST ALTER COLUMN CAREPACK_ST_DT DATE
GO
ALTER TABLE ##TEMP_TEST ALTER COLUMN CAREPACK_END_DT DATE
GO
ALTER TABLE ##TEMP_TEST ALTER COLUMN INS_GMT_TS DATETIME2
GO
ALTER TABLE ##TEMP_TEST ALTER COLUMN UPD_GMT_TS DATETIME2
GO
Please let me know.
Thanks and Regards Rajesh

Answer 1

Hi ,
We are using SQL Server 2008 SP3. 
Thanks and Regards Rajesh
Then what you can do is to run a set of updates as below
UPDATE t
SET CAREPACK_ST_DT = NULL
FROM ##TEMP_TEST t
WHERE ISDATE(CAREPACK_ST_DT) = 0
AND LEN(CAREPACK_ST_DT) < 8
UPDATE t
SET CAREPACK_END_DT = NULL
FROM ##TEMP_TEST t
WHERE ISDATE(CAREPACK_END_DT) = 0
AND LEN(CAREPACK_END_DT) < 8
UPDATE t
SET INS_GMT_TS = NULL
FROM ##TEMP_TEST t
WHERE ISDATE(INS_GMT_TS) = 0
AND LEN(INS_GMT_TS) < 8
UPDATE t
SET UPD_GMT_TS = NULL
FROM ##TEMP_TEST t
WHERE ISDATE(UPD_GMT_TS) = 0
AND LEN(UPD_GMT_TS) < 8
And then do the date conversion using ALTER statements
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Visakh
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