收获，不止oracle
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编辑 删除
count(*)优化
SQL> create table t1 as select * from dba_objects;表已创建。SQL> create index idx1_object_id on t1(object_id);索引已创建。SQL> select count(*) from t1; COUNT(*)---------- 49821思考一个问题，count(*)是否走索引?验证一下SQL> select count(*) from t1; COUNT(*)...
