numeric

TRUNC()

Truncates a number toward zero, removing digits past a given precision.

Description

TRUNC cuts off digits beyond a specified number of decimal places, moving toward zero (unlike ROUND, it never rounds). TRUNC(3.987, 1) is 3.9, and TRUNC(-3.987, 1) is -3.9. It's ideal when you want to drop precision without rounding up or down.

Syntax

TRUNC(expression)
TRUNC(expression, n)

Parameters

Name	Description	Optional
expression	A numeric column or expression.	No
n	Decimal places to keep (default 0).	Yes

Return Type

Returns the same numeric type as the input.

Examples

Store (Customers/Orders/Products)

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Store (Customers/Orders/Products)

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TRUNC vs ROUND

TRUNC just chops digits; ROUND adjusts the last kept digit. Use TRUNC when you must not round.

Common Mistakes

Expecting rounding. TRUNC never rounds — TRUNC(3.9) is 3, not 4.
Confusing with FLOOR. TRUNC moves toward zero; FLOOR moves down. TRUNC(-3.9) is -3, FLOOR(-3.9) is -4.
Wrong precision sign. A negative n truncates to the left of the decimal.