Common mistake

SQL Integer Division: Percentages Come Out 0

In many SQL engines, dividing two integers can truncate the fraction. Multiply by 100.0 and round.

The symptom

You compute a rate like shipped / total and every value comes back 0 or a whole number in some databases, even though the real answer is a fraction like 0.708.

Why it happens

In engines such as Postgres and SQL Server, dividing one integer by another does integer division, which throws away the remainder. 17 / 24 becomes 0, not 0.708.

The fix

Force the math to be fractional by making one side a decimal. The cleanest trick is to start a percentage with 100.0. Then round() for a tidy result.

Risky in many engines

select shipped / total as rate   -- can truncate to 0

Right

select round(100.0 * shipped / total, 1) as pct
-- 100.0 is a decimal-friendly, portable habit

DuckDB note

DuckDB (which powers SQLShed) actually does fractional division with / by default, so 17 / 24 is 0.708 here. The 100.0 habit costs nothing and keeps your query portable to engines where integer division truncates.