DS0-001 · Question #83
DS0-001 Question #83: Real Exam Question with Answer & Explanation
The correct answer is A: DISTINCT. DISTINCT is the correct SQL qualifier because it filters out duplicate rows from a result set, returning only unique combinations of the selected columns - e.g., SELECT DISTINCT city FROM customers. SINGLE is not a valid SQL keyword in any standard dialect. UNIQUE is a constraint
Question
Which of the following qualifiers removes duplicate records from a SQL SELECT statement when included in a query?
Options
- ADISTINCT
- BSINGLE
- CUNIQUE
- DTOP 1
Explanation
DISTINCT is the correct SQL qualifier because it filters out duplicate rows from a result set, returning only unique combinations of the selected columns - e.g., SELECT DISTINCT city FROM customers. SINGLE is not a valid SQL keyword in any standard dialect. UNIQUE is a constraint used in table definitions (CREATE TABLE) to enforce uniqueness on a column, not a SELECT qualifier. TOP 1 limits results to one row (SQL Server syntax), which isn't the same as deduplication - it would still return a duplicate if that single row happened to repeat.
Memory tip: Think "DISTINCT = different" - you want results that are distinctly different from each other, with no repeats.
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