CompTIA Data+ DA0-002 (V2) Practice Question

The correct answer is to use a regular expression (RegEx). A regular expression is the most effective and scalable method for this task because it allows for pattern-based searching and replacement. A single RegEx pattern, such as [^0-9] or \D, can identify all characters that are not digits in one operation, regardless of what the specific characters are.

• Applying nested REPLACE functions is incorrect because it is inefficient and not robust. While it could work for the specific examples given, it would fail if new, unanticipated non-numeric characters (like spaces or other symbols) were present in the data. The analyst would need to add a new nested REPLACE for every possible character, making the query complex and hard to maintain.
• Using the TRIM function is incorrect. The TRIM function is designed to remove characters or whitespace from the beginning or end of a string, not from the middle. It would not be able to remove the internal characters like ) or - in (555) 123-4567.
• Converting the column's data type directly to an integer is incorrect because it will cause an error. Most database systems cannot cast a string that contains non-numeric characters (like parentheses, spaces, or hyphens) to a numeric data type and will raise a conversion error. The non-numeric characters must be removed before attempting any data type conversion.