请问以下两个执行计划那个更好?
其中item_safety表有100万数据,safety_type大概有20条数据
I_SAFETY_ID 是ITEM_SAFETY表的索引,字段:safety_id关联SAFETY_TYPE表SELECT STATEMENT, GOAL = CHOOSE
SORT GROUP BY
TABLE ACCESS BY INDEX ROWID Object owner=DEV Object name=ITEM_SAFETY
NESTED LOOPS
TABLE ACCESS FULL Object owner=DEV Object name=SAFETY_TYPE
INDEX RANGE SCAN Object owner=DEV Object name=I_SAFETY_ID
SELECT STATEMENT, GOAL = CHOOSE
SORT GROUP BY
NESTED LOOPS
TABLE ACCESS FULL Object owner=DEV Object name=ITEM_SAFETY
TABLE ACCESS BY INDEX ROWID Object owner=DEV Object name=SAFETY_TYPE
INDEX UNIQUE SCAN Object owner=DEV Object name=PK_SAFETY_TYPE
其中item_safety表有100万数据,safety_type大概有20条数据
I_SAFETY_ID 是ITEM_SAFETY表的索引,字段:safety_id关联SAFETY_TYPE表SELECT STATEMENT, GOAL = CHOOSE
SORT GROUP BY
TABLE ACCESS BY INDEX ROWID Object owner=DEV Object name=ITEM_SAFETY
NESTED LOOPS
TABLE ACCESS FULL Object owner=DEV Object name=SAFETY_TYPE
INDEX RANGE SCAN Object owner=DEV Object name=I_SAFETY_ID
SELECT STATEMENT, GOAL = CHOOSE
SORT GROUP BY
NESTED LOOPS
TABLE ACCESS FULL Object owner=DEV Object name=ITEM_SAFETY
TABLE ACCESS BY INDEX ROWID Object owner=DEV Object name=SAFETY_TYPE
INDEX UNIQUE SCAN Object owner=DEV Object name=PK_SAFETY_TYPE
解决方案 »
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