DateAdd¶

Overview¶

The DateAdd expression adds a specified number of days to a given date value. It is a binary expression that takes a date and an integer representing the number of days to add, returning a new date value.

Syntax¶

date_add(start_date, num_days)

// DataFrame API usage
df.select(date_add(col("date_column"), lit(5)))

Arguments¶

Argument	Type	Description
startDate	DateType	The base date to which days will be added
days	IntegerType, ShortType, ByteType	The number of days to add (can be negative for subtraction)

Return Type¶

DateType - Returns a date value representing the original date plus the specified number of days.

Supported Data Types¶

Input: DateType for the first argument, numeric types (IntegerType, ShortType, ByteType) for the second argument
Output: DateType

Algorithm¶

Takes the input date as an internal integer representation (days since epoch)
Converts the days parameter to an integer value using intValue()
Performs simple integer addition: start.asInstanceOf[Int] + d.asInstanceOf[Number].intValue()
Returns the result as a date value
Uses null-safe evaluation to handle null inputs properly

Partitioning Behavior¶

This expression preserves partitioning as it operates on individual rows without requiring data movement:

Does not require shuffle operations
Maintains existing data distribution
Can be executed locally on each partition

Edge Cases¶

Null handling: Returns null if either input argument is null (null-intolerant behavior)
Negative values: Supports negative day values to subtract days from the date
Overflow: May produce unexpected results if the calculation exceeds valid date ranges
Type conversion: Automatically converts ShortType and ByteType to integers for calculation

Code Generation¶

This expression supports Tungsten code generation through the doGenCode method, which generates optimized Java code for better performance rather than falling back to interpreted evaluation.

Examples¶

-- Add 1 day to a specific date
SELECT date_add('2016-07-30', 1);
-- Result: 2016-07-31

-- Subtract 5 days using negative value
SELECT date_add('2023-01-15', -5);
-- Result: 2023-01-10

-- Use with table columns
SELECT date_add(order_date, 30) as due_date FROM orders;

// DataFrame API usage
import org.apache.spark.sql.functions._

// Add days to a date column
df.select(date_add(col("start_date"), lit(7)).alias("end_date"))

// Use with variable days
df.select(date_add(col("order_date"), col("processing_days")))