Question

The SELECT command when combined with DISTINCT clause is used to:

• A. returns records without repetition
• B. returns records with repetition
• C. returns all records with conditions
• D. returns all records without checking

Hint:

Always use DISTINCT when you want to remove duplicates and retrieve only unique results in SQL queries.

Answer 1

The Correct Option is A

Step 1: Understanding DISTINCT.
The DISTINCT keyword in SQL is used to retrieve only unique values from a result set, effectively removing any duplicate records.
Step 2: Example.
Consider a column with values: (10, 20, 10, 30).
\begin{verbatim}SELECT DISTINCT column_name FROM table;\end{verbatim} Executing this query will yield the result: (10, 20, 30).
Step 3: Eliminate wrong options.
- Option 2: Incorrect, as DISTINCT's purpose is to exclude duplicates.
- Option 3: Incorrect, as filtering is done via the WHERE clause, not DISTINCT.
- Option 4: Incorrect, as DISTINCT explicitly identifies and removes duplicate entries.

Final Answer: \[\boxed{\text{Returns records without repetition}}\]