Bits of .NET

CAST throws error on invalid data. TRY_CAST returns NULL instead – safer for user input.

CAST – Throws Error:

SELECT CAST('123' AS INT);  -- Works: 123
SELECT CAST('abc' AS INT);  -- Error: Conversion failed!
-- Query crashes, returns nothing

TRY_CAST – Returns NULL:

SELECT TRY_CAST('123' AS INT);  -- Returns: 123
SELECT TRY_CAST('abc' AS INT);  -- Returns: NULL (no error)
-- Query continues, you can handle NULL

Real-World Usage:

-- Import messy user data
SELECT 
    Name,
    TRY_CAST(Age AS INT) AS Age,
    TRY_CAST(SignupDate AS DATE) AS SignupDate
FROM ImportedData
WHERE TRY_CAST(Age AS INT) IS NOT NULL;  -- Filter out invalid ages

Also Available: TRY_CONVERT, TRY_PARSE for similar safe conversions