The Correct Answer and Explanation is:
The correct query is:
SELECT name, email FROM employees LIMIT 25;
This SQL query is the most accurate and efficient solution for the stated problem. Let’s break down why it is the correct choice and why the other options are incorrect.
The goal is to review the “name” and “email” columns from a large “employees” table by examining a small sample of records. The correct query perfectly addresses each part of this requirement. The SELECT name, email clause specifically targets only the two columns of interest. This is more efficient than selecting all columns, especially in a large table with many columns, as it reduces the amount of data that the database needs to process and send.
The FROM employees clause correctly identifies the table from which to retrieve the data. This is standard SQL syntax for specifying the data source.
Finally, the LIMIT 25 clause is essential. The problem states the table is “large” and the goal is to “examine a few records.” The LIMIT clause restricts the output to the first 25 rows found, preventing the query from returning millions of records, which would be slow and unmanageable. This makes it an ideal tool for quickly sampling or previewing data.
The other options contain significant errors:
- SELECT SUM(name, email) FROM employees; is incorrect because SUM() is an aggregate function for numerical data, not for text fields like names and emails.
- SELECT name, email FROM employees MAX(25); uses invalid syntax. MAX() is a function to find the maximum value in a column, not to limit the number of rows.
- SELECT * FROM employees.name, email LIMIT 25; has incorrect syntax in the FROM clause. The table name should be employees, not employees.name, email.
- SELECT * FROM employees LIMIT 25; is syntactically valid, but it is less precise. It retrieves all columns (*) instead of just the requested “name” and “email” columns, making it less efficient.
