在Oracle SQL中,要有效利用索引进行去重操作,可以采用以下方法:
SELECT DISTINCT column1, column2 FROM table_name;
SELECT column1, column2 FROM table_name GROUP BY column1, column2;
SELECT * FROM table_name WHERE ROWID IN (SELECT MIN(ROWID) FROM table_name GROUP BY column1, column2);
SELECT column1, column2 FROM table_name t1
WHERE EXISTS (SELECT 1 FROM table_name t2
WHERE t1.column1 = t2.column1
AND t1.column2 = t2.column2
AND t1.rowid > t2.rowid);
通过以上方法,可以有效利用索引进行去重操作,提高查询性能。
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