Sort by Minimum Value of Two Columns

No LEAST? No problem!

SQL Server is a bit picky; it doesn't support LEAST. But worry not, a CASE expression can do the trick:

/* Mother of all case statements - starts */
SELECT * 
FROM your_table 
ORDER BY CASE 
    WHEN col1 < col2 OR col2 IS NULL THEN col1 
    ELSE col2 
END; /* Mother of all case statements - ends */


NULLOSAURUSrex Strikes! Handling NULLs with ANSI Standard

Damn those NULL values. Good news, though. COALESCE is not just a fancy SQL term; it adheres to the ANSI SQL standards and is the NULLOSAURUSrex slayer:

// Amaze your friends. Teach your grandma. 
ORDER BY CASE 
    WHEN COALESCE(col1, col2) < COALESCE(col2, col1) THEN col1 
    ELSE col2 
END;


Handle datetime like a boss using a reference date compatible with the ANSI standard date format, aka '1753-01-01':

// Because old is always gold, right?
ORDER BY CASE
    WHEN COALESCE(Date1, '1753-01-01') < COALESCE(Date2, '1753-01-01')
    THEN Date1
    ELSE Date2
END;


Running Circles Around Nested Selects

For more complex queries, a nested SELECT can help you find the minimum date and sort efficiently:

// Say hello to nested SELECT. KEEP CALM AND NEST ON.
SELECT *, 
    (SELECT MIN(d) FROM (VALUES (Date1), (Date2)) AS a(d)) AS MinDate
FROM your_table
ORDER BY MinDate;


Who said elegance and efficiency can't coexist in SQL? Nesting SELECT gives you both!

Calculate Minimum Datetime Value Like a Pro

You're dealing with multiple datetime columns? No sweat. DATEDIFF and ABS are your knights in shining armor:

// Make the calculation. Be the calculation.
SELECT *, 
    ABS(DATEDIFF(day, '1753-01-01', COALESCE(Date1, '1753-01-01'))) AS Diff1,
    ABS(DATEDIFF(day, '1753-01-01', COALESCE(Date2, '1753-01-01'))) AS Diff2
FROM your_table
ORDER BY CASE
    WHEN Diff1 < Diff2 THEN Date1
    ELSE Date2
END;


This technique applies to both numerical and date values, preserving a consistent sorting order even when NULL values want to spoil the party (yeah, they do that).

SQL Performance: The Need for Speed

We all know time is money. Thinking about performance? CASE expressions are usually efficient, but remember nested queries can slow you down. Choose wisely, my friend.

Don't Fall in the Pitfalls

When handling NULL values, COALESCE is your safety net. It's more standard-compliant than ISNULL, ensuring your scripts are compatible across SQL systems.

Remember, unhandled NULL values can lead to unexpected results. Tame them with a well-crafted CASE statement or the magic of COALESCE.