coalescea

COALESCEa is a hypothetical data transformation function in data-processing contexts, presented as an extended version of SQL's COALESCE. It returns the first non-null value among its inputs and adds support for explicit defaults and nested or complex data.

Basic usage follows COALESCE: COALESCEa(a, b, c, defaultVal) yields the first non-null among a, b, c; if all are null, it returns defaultVal when provided, otherwise null.

When inputs include arrays or objects, COALESCEa traverses elements or fields from left to right to locate a non-null value. It may also apply a path into nested data, such as COALESCEa(data.user.address.city, data.contact.city, 'unknown'), to reach a non-null field.

An optional type-coercion setting allows the result to be cast to a target type to reduce downstream errors. The function is commonly used in ETL workflows, data cleaning, and analytics where missing values and irregular schemas occur.

COALESCEa differs from COALESCE mainly by its nested-data awareness, explicit defaults, and optional coercion controls. It is not a standard SQL feature; implementations vary, and performance can be a concern with large or deeply nested inputs. See also: COALESCE, NULL, IS NULL, NULLIF.