First non null value (coalesce)

Supported in: Batch, Streaming

Picks first non null value of the inputs. Known as coalesce in sql.

Expression categories: Data preparation

Declared arguments

• Expressions - The first non null values of these expressions will be returned.
  List<Expression<T>>
• optional Treat empty strings as null. - Treat all empty strings as null values.
  Literal<Boolean>

Type variable bounds: T accepts AnyType

Output type: T

Examples

Example 1: Base case

Argument values:

• Expressions: [tail_number, airline]
• Treat empty strings as null.: null

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Example 2: Base case

Argument values:

• Expressions: [tail_number, airline]
• Treat empty strings as null.: true

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Example 3: Null case

Argument values:

• Expressions: [tail_number, airline]
• Treat empty strings as null.: null

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