TRUNC Function

Removes all digits to the right of the decimal point for any value. Optionally, you can specify the number of digits to which to round. Input can be an Integer, a Decimal, a column reference, or an expression.

Wrangle vs. SQL: This function is part of Wrangle, a proprietary data transformation language. Wrangle is not SQL. For more information, see Wrangle Language.

Basic Usage

Numeric literal example:

trunc(pi())

Output: Returns the value 3.

Expression example:

trunc(length_in * length_in, 2)

Output:Returns the square of the values in length_in, truncated to two decimal points.

Syntax and Arguments

trunc(numeric_value,integer_value)

Argument	Required?	Data Type	Description
numeric_value	Y	string, decimal, or integer	Name of column or Decimal or Integer literal to apply to the function
integer_value	N	integer	Number of digits to which to truncate. Default is `0`, which truncates to the nearest integer. Negative integer values can be applied.

For more information on syntax standards, see Language Documentation Syntax Notes.

numeric_value

Name of the column, numeric literal, or numeric expression.

Missing input values generate missing results.
Literal numeric values should not be quoted. Quoted values are treated as strings.
Multiple columns and wildcards are not supported.

Usage Notes:

Required?	Data Type	Example Value
Yes	String (column reference) or Integer or Decimal literal	2.5

integer_value

Number of digits to which to round the first argument of the function.

Positive values values truncate to the right of the decimal point.
Negative values truncate to the left of the decimal point.
Missing input values generate missing results.

Usage Notes:

Required?	Data Type	Example Value
No	Integer literal	3

Examples

提示

For additional examples, see Common Tasks.

Example - Basic TRUNC

Source:

RowId	myVal
r01	1.2345
r02	-1.2345
r03	100.000
r04	10.1
r05	50.029

Transformation:

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	trunc(myVal)
Parameter: New column name	'trunc_myVal'

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	trunc(myVal,2)
Parameter: New column name	'trunc_myVal2'

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	trunc(myVal,2)
Parameter: New column name	'trunc_myVal_2'

Results:

RowId	myVal	trunc_myVal	trunc_myVal2	trunc_myVal_2
r01	1.2345	1	1.23	0
r02	-1.2345	-1	-1.23	0
r03	100.000	100	100.00	100
r04	10.1	10	10.1	0
r05	50.029	50	50.02	0

Example - RANDBETWEEN, PI, and TRUNC functions

This example illustrates how you can apply functions to generate random numeric data in your dataset.

Functions:

Item	Description
RANDBETWEEN Function	Generates a random integer between a low and a high number. Two inputs may be Integer or Decimal types, functions returning these types, or column references.
PI Function	The `PI` function generates the value of pi to 15 decimal places: 3.1415926535897932.
ROUND Function	Rounds input value to the nearest integer. Input can be an Integer, a Decimal, a column reference, or an expression. Optional second argument can be used to specify the number of digits to which to round.
TRUNC Function	Removes all digits to the right of the decimal point for any value. Optionally, you can specify the number of digits to which to round. Input can be an Integer, a Decimal, a column reference, or an expression.
POW Function	Computes the value of the first argument raised to the value of the second argument.

Source:

In the following example, a company produces 10 circular parts, the size of which is measured in each product's radius in inches.

prodId	radius_in
p001	1
p002	2
p003	3
p004	4
p005	5
p006	6
p007	7
p008	8
p009	9
p010	10

Based on the above data, the company wants to generate some additional sizing information for these circular parts, including the generation of two points along each part's circumference where quality stress tests can be applied.

Transformation:

To begin, you can use the following steps to generate the area and circumference for each product, rounded to three decimal points:

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	ROUND(PI() * (POW(radius_in, 2)), 3)
Parameter: New column name	'area_sqin'

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	ROUND(PI() * (2 * radius_in), 3)
Parameter: New column name	'circumference_in'

For quality purposes, the company needs two tests points along the circumference, which are generated by calculating two separate random locations along the circumference. Since the RANDBETWEEN function only calculates using Integer values, you must first truncate the values from circumference_in:

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	TRUNC(circumference_in)
Parameter: New column name	'trunc_circumference_in'

Then, you can calculate the random points using the following:

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	RANDBETWEEN(0, trunc_circumference_in)
Parameter: New column name	'testPt01_in'

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	RANDBETWEEN(0, trunc_circumference_in)
Parameter: New column name	'testPt02_in'