TSQL TRY_CAST, TRY_PARSE & TRY_CONVERT

Normally if you use a CAST, PARSE or CONVERT the whole statement fails if a value can’t be cast, parsed or converted. If you use the TRY_ version you get a NULL result if the conversion fails without an error.

SELECT CAST(N'ABC' as INT) as CastResult;
--Conversion failed when converting the nvarchar value 'ABC' to data type int.

SELECT TRY_CAST(N'ABC' as INT) as CastResult;
-- Result NULL

SELECT PARSE('$345,98' AS money USING 'nl-NL') as ParseResult;
-- Error converting string value '$345,98' into data type money using culture 'nl-NL'.
-- (They use Euro's in NL)

SELECT TRY_PARSE('$345,98' AS money USING 'de-DE') AS ParseResult;
-- Result Null

SET DATEFORMAT dmy;
SELECT CONVERT(datetime2, '12/31/2010') AS ConvertResult;
-- Conversion failed when converting date and/or time from character string.

SET DATEFORMAT dmy;
SELECT TRY_CONVERT(datetime2, '12/31/2010') AS ConvertResult;
-- Result Null

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