Data Engineering Associate with Databricks Practice Exam

Which function can be used to perform filtering with a lambda expression in SQL?

1. Transform()

2. FILTER()

3. Map()

4. Explode()

The correct answer is: FILTER()

The function that is most appropriate for performing filtering with a lambda expression in SQL is the FILTER() function. This function allows you to specify a condition based on a lambda expression to determine which rows of data should be included in the output. FILTER() effectively applies the specified condition and returns only the records that meet the criteria defined by the lambda expression. This is particularly useful when you need to narrow down a dataset based on specific characteristics or values, allowing for more focused data analysis. In contrast, the other functions serve different purposes. For instance, Transform() modifies each element of a dataset using a provided function but does not inherently filter results. Map() similarly applies a function to each element but is not designed specifically for filtering purposes. Explode() is used for transforming array or map columns into separate rows, which also does not fit the criteria for filtering based on a condition. Hence, FILTER() is the correct choice as it directly relates to the task of filtering data in conjunction with lambda expressions.