truncate function

The trunc function truncates the value of an input expression to the specified decimal places on the right of the decimal point.

Syntax:

double trunc(n [, d ])

Semantics:

• n, d: The arguments n and d are expressions that resolve to numbers. The value of d must be in the range of -30 <=d<=30. Any value of d exceeding the maximum absolute value of 30 is truncated to 30 or -30 respectively. If d is not an integer, it is cast to an integer value.

  For example, trunc(123.456,1.5) is considered trunc(123.456,1), and trunc(123.456,50) is treated as trunc(123.456,30).

• return type: double. Depending on the values of n and d, the trunc function behaves as follows:

  • If d is a positive value, the function truncates n to d places on the right of the decimal point, that is, retains only d decimal digits to the right of the decimal point.

  • If d is greater than or equal the number of digits to the right of the decimal point in n, the value of n is returned.

  • If d is not specified or zero, the function truncates n to zero places.

  • If d is a negative value, the function truncates n to the left of the decimal point, that is, sets d digits to the left of the decimal point to zero. The right of the decimal point is also set to zero. If the number of digits in n to the left of the decimal point is less than or equal to the absolute value of d, then the function returns 0.0.

  • Returns zero if n is zero, regardless of the value of d (except when d is NULL).

  • Returns a NULL value in the following cases:

    • If either of the arguments is a NULL value

    • If either of the arguments does not resolve to a number

  • Returns n if either of the arguments resolves to a NaN or infinity.

Example 1 - truncate function

SELECT trunc(n,d) FROM Userstocks

Value of n	Value of d	Output
111.567	0 or not specified	100.00
111.567	2	100.56
111.567	3	111.567
111.567	-2	100.0
111.567	-3	0.0
-111.567	2	-100.567
-111.567	-1	-110.0