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? 2 - access("T1"."OBJECT_ID"="T2"."OBJECT_ID")
统计信息
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? ? ? ? ? 3? recursive calls
? ? ? ? 103? db block gets
? ? ? 25? consistent gets
? ? ? ? ? 0? physical reads
? ? ? 23736? redo size
? ? ? ? 561? bytes sent via SQL*Net to client
? ? ? ? 858? bytes received via SQL*Net from client
? ? ? ? ? 3? SQL*Net roundtrips to/from client
? ? ? ? ? 2? sorts (memory)
? ? ? ? ? 0? sorts (disk)
? ? ? ? ? 99? rows processed
?
SQL> commit;
? 总结：可以看到，第二种写法比第一种写法少扫描一张表，逻辑读也少了很多。
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