- ORACLE内部操作
当执行查询时,ORACLE采用了内部的操作. 下表显示了几种重要的内部操作.
ORACLE Clause
内部操作
ORDER BY
SORT ORDER BY
UNION
UNION-ALL
MINUS
MINUS
INTERSECT
INTERSECT
DISTINCT,MINUS,INTERSECT,UNION
SORT UNIQUE
MIN,MAX,COUNT
SORT AGGREGATE
GROUP BY
SORT GROUP BY
ROWNUM
COUNT or COUNT STOPKEY
Queries involving Joins
SORT JOIN,MERGE JOIN,NESTED LOOPS
CONNECT BY
CONNECT BY