Convert varchar into datetime in SQL Server

Decrypting custom date formats

A sword will hurt you if you hold it by the blade. Similarly, a date in the wrong format stings. Here's your shield!

Maneuvering through string format

To deal with a VARCHAR date in mmddyyyy format, rearrange and transform:

SELECT CONVERT(DATETIME, 
     SUBSTRING(your_varchar_column, 5, 4) +  -- Year
     SUBSTRING(your_varchar_column, 1, 2) +  -- Month
     SUBSTRING(your_varchar_column, 3, 2)    -- Day
) AS NewDateTime
FROM your_table;


'YYYYMMDD' is SQL Server's favorite dessert!

Pre-conversion safety checks using ISDATE()

Prevention is better than error messages. Check if your VARCHAR is a valid date before conversion:

SELECT your_varchar_column
FROM your_table
WHERE ISDATE(your_varchar_column) = 1;
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Explicit conversions yield explicit results

Implicit casting is a bit like surprise parties, amusing but unpredictable. Choose explicit conversion:

SELECT CONVERT(DATETIME, 
     -- Hogwarts School of String Manipulation and Conversion
) AS NewDateTime
FROM your_table;


Watch out for banana peels

Incorrect string formats are banana peels for your SQL statement. Don't let them make you slip with out-of-range errors. Validate, Validate, Validate!

Wisdom on adapting to the quirks and caprices of dates

Formats are ARMY, SQL style codes are allies

SQL Server understands many date formats, as denoted by the style codes. But like in any alliance, choosing the wrong allies can lead to confusion. Know your codes!

'YYYYMMDD' => The passport to compatibility

This configuration is universally accepted across SQL Server versions. So, keep your date variables stored in the 'YYYYMMDD' format. Safe travels!

The Holy Grail of SQL Server - Documentation

Ever felt lost while coding? SQL Server documentation is your map! Always keep this close and refer to it regularly.

Flex and adapt

You never know what you'll get when dealing with VARCHARs that might be dates. Design your functions to be as nimble as a gymnast and adapt to different date input patterns.