Data Engineering Associate with Databricks Practice Exam

In SQL, which function is appropriate for extracting specific patterns from strings with regex?

1. REGEXP_EXTRACT()

2. STRING_EXTRACT()

3. PATTERN_MATCH()

4. EXTRACT_REGEX()

The correct answer is: REGEXP_EXTRACT()

The function REGEXP_EXTRACT() is designed specifically for working with regular expressions in SQL. It enables users to extract substrings from a given string based on a specified regex pattern. This function is particularly useful in scenarios where you need to isolate parts of a string that match a certain format or pattern, such as extracting dates, email addresses, or other structured data from unstructured text. Using REGEXP_EXTRACT(), you can specify both the source string and the regex pattern, allowing for powerful and flexible string manipulation capabilities. This functionality is integral in data processing tasks where one needs to cleanse or transform data as part of ETL (Extract, Transform, Load) operations. The other options provide names that do not correctly correspond to standard SQL functions, which may lead to confusion. For example, STRING_EXTRACT() suggests the ability to extract strings but lacks the regex capability that REGEXP_EXTRACT() offers. Similarly, PATTERN_MATCH() and EXTRACT_REGEX() do not refer to standard SQL functions recognized for string manipulation with regular expressions. Therefore, the selection of REGEXP_EXTRACT() is aligned with established SQL practices for extracting specific patterns from strings using regex.