The correct answer is that the query will return incorrect results because string comparison is lexicographic. When dates are stored as strings in 'MM/DD/YYYY' format, SQL compares them character by character from left to right, not as chronological values. For example, '01/02/2023' (January 2) is considered greater than '12/31/2022' because the first character '0' is greater than '1', completely ignoring the actual date order. On the CompTIA Data+ DA0-001 exam, this concept tests your understanding of data type pitfalls and the importance of storing dates in proper date formats or ISO 8601 (YYYY-MM-DD) for accurate sorting. A common trap is assuming SQL will automatically interpret a string as a date, but it never does—it simply compares text. To remember this, think: "Months first, not meaning first"—the leading month digit dictates the sort, not the actual calendar sequence.
DA0-001 Mining and Acquiring Data Practice Question
This DA0-001 practice question tests your understanding of mining and acquiring data. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Exhibit
SELECT * FROM sales WHERE date BETWEEN '2023-01-01' AND '2023-12-31';
Refer to the exhibit. If the date column is stored as a string in 'MM/DD/YYYY' format, what will be the result?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Incorrect results because string comparison is lexicographic.
Option A is correct because when dates are stored as strings in 'MM/DD/YYYY' format, string comparison is lexicographic (character-by-character). This means that '01/02/2023' (January 2) would be considered greater than '12/31/2022' because '0' > '1' at the first character, leading to incorrect chronological ordering. The comparison does not interpret the string as a date value.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Incorrect results because string comparison is lexicographic.
Why this is correct
The different format causes lexicographic comparison to fail.
Related concept
Read the scenario before looking for a memorised answer.
✗
NULL values
Why it's wrong here
The query does not produce NULLs; it may return no rows or incorrect rows.
✗
Error because DATE type is expected.
Why it's wrong here
The query will run, but the comparison will be string-based.
✗
Correct results because string comparison works for dates.
Why it's wrong here
String comparison does not recognize date semantics and will compare character by character.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CompTIA often tests the misconception that string comparison of dates in 'MM/DD/YYYY' format will yield correct chronological order, but the trap is that lexicographic comparison compares month first, not year, leading to incorrect results.
Detailed technical explanation
How to think about this question
Under the hood, lexicographic comparison uses the ASCII or Unicode code point of each character sequentially. For 'MM/DD/YYYY', the month field is compared first, so all dates in January (01) will appear before dates in February (02) regardless of the year or day, breaking chronological sorting. In real-world scenarios, this is a common pitfall when importing data from CSV files or logs where dates are stored as strings without explicit conversion to a DATE or TIMESTAMP type.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the DA0-001 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Mining and Acquiring Data — This question tests Mining and Acquiring Data — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Incorrect results because string comparison is lexicographic. — Option A is correct because when dates are stored as strings in 'MM/DD/YYYY' format, string comparison is lexicographic (character-by-character). This means that '01/02/2023' (January 2) would be considered greater than '12/31/2022' because '0' > '1' at the first character, leading to incorrect chronological ordering. The comparison does not interpret the string as a date value.
What should I do if I get this DA0-001 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Refer to the exhibit. What is the most likely issue causing the unexpectedly low count?
medium
A.The customers table is indexed incorrectly
B.The query is missing a GROUP BY clause
C.The database was not refreshed
✓ D.The signup_date column is in a different date format
Why D: Option A is correct because if the signup_date column is stored in a different date format (e.g., MM/DD/YYYY), the comparison with '2023-01-01' (YYYY-MM-DD) may not match many records. Option B is wrong because GROUP BY is not needed for COUNT(*). Option C is wrong because database refresh does not directly affect query result. Option D is wrong because indexing affects performance, not correctness.
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Question Discussion
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