問題文
A query selects a department identifier and a job identifier from an employee table and places DISTINCT right after the SELECT keyword. The result holds more rows than the number of distinct department identifiers. Which statement explains the row count?
選択肢
- The keyword removes duplicates from the first listed column so each department value yields one row and job values repeat.
- The keyword removes duplicates across the whole select list so each pair of department and job values yields one row.
- The keyword removes duplicates within each group of rows so departments with many jobs give several rows.
- The keyword removes duplicates after the sort finishes so rows that share a department value stay apart.