ClickHouse ® tips #7: Forward and backfilling null values

When dealing with datasets containing null values, it's often necessary to fill these gaps with non-null values to maintain data integrity. While a constant value can be used as a substitute, a more dynamic approach involves filling nulls with the latest or next available value, a task made simple in libraries like Pandas through the fillna method, and similarly achievable in Postgres. ClickHouse® also supports this functionality using array functions, providing a detailed explanation of the process and the specific role of each array function within the subqueries used to handle such replacements.