drop table t;CREATE TABLE T AS SELECT * FROM DBA_OBJECTS;CREATE OR REPLACE FUNCTION F_NO_RESULT_CACHE RETURN NUMBER ASV_RETURN NUMBER;BEGINSELECT COUNT(*) INTO V_RETURN FROM T;RETURN V_RETURN;END;/set autotrace on statisticsSELECT F_NO_RESULT_CACHE FROM DUAL;--看调用F_NO_RESULT_CACHE执行第2次后的结果SELECT F_NO_RESULT_CACHE FROM DUAL;CREATE OR REPLACE FUNCTION F_RESULT_CACHE RETURN NUMBER RESULT_CACHE AS V_RETURN NUMBER; BEGIN SELECT COUNT(*) INTO V_RETURN FROM T; RETURN V_RETURN; END;/SELECT F_RESULT_CACHE FROM DUAL;--看调用F_RESULT_CACHE执行第2次后的结果SELECT F_RESULT_CACHE FROM DUAL;