Remove trailing zeros from decimal in SQL Server

Understanding data accuracy and impact

Here's the kicker, when we convert to a float, we're doing a floating-point representation which might not keep up with precision. We’re in the decimals game here, every little counts.

To maintain precision, avoid CAST as FLOAT/REAL for decimal types like decimal(9,6). They guarantee accuracy via a fixed scale. (Lessons learned: accuracy matters, not just in SQL.)

Precision and data integrity

If your data can't tolerate a rounding error even at the sixth decimal place, (high five, fellow perfectionist!), use the STR function.

SELECT STR(column_name, 10, 6) 
-- Takes precision seriously, removes trailing zeros, and still respects data integrity
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Heads up, FORMAT() can achieve the same but might need some caffeine (a.k.a performance could be slower) because of CLR runtime.

Client-side vs server-side formatting

For the ones who like it clean, consider client-side formatting. It circumvents regional settings variation issues in SSMS and also ensures data stays intact:

decimal value = 10.5000m;
string displayValue = value.ToString("0.0####"); 
-- Drops the mic on trailing zeros without bothering the original data
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Three words for .NET custom numeric format strings - they’re a lifesaver!

Exploring other trimming methods

If CAST as FLOAT makes you nauseous, we've got alternatives.

SELECT REVERSE(CAST(ROUND(REVERSE(column_name), 2) AS NVARCHAR(20))) FROM table_name; 
-- If reversing the world removes trailing zeros, let’s do it!
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Make sure it answers all your decimal inputs correctly. Beware of potential scientific notations for very small decimals.

Performance implications

Do not discount the execution plan just like how you cannot ignore the nutrition facts on your pizza box. Make sure your conversions aren't stealing too much performance.

Rounding issues and consistency

Some methods like using FLOAT might bake in rounding errors. The solution? AVOID FLOAT/REAL for precision-critical tasks.

Safer conversions using TRY_CAST

When data threatens to fail conversion due to formatting, TRY_CAST is your SQL bat-signal:

SELECT TRY_CAST(column_name AS FLOAT) FROM table_name;
-- Safer streets in Gotham, nulls instead of errors when conversion fails!
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