最近oracle使用总结
1：查看sql的执行计划
explain plan for sql
然后执行select * from table(dbms_xplan.display());
例如
explain plan for select rownum no,id,name from product_group order by name
然后执行select * from table(dbms_xplan.display());
输出为
?
-----------------------------------
| Id? | Operation??????????? |? Name????????? | Rows? | Bytes | Cost? |
-----------------------------------
|?? 0 | SELECT STATEMENT???? |??????????????? |?????? |?????? |?????? |
|?? 1 |? SORT ORDER BY?????? |??????????????? |?????? |?????? |?????? |
|?? 2 |?? COUNT????????????? |??????????????? |?????? |?????? |?????? |
|?? 3 |??? TABLE ACCESS FULL | PRODUCT_GROUP? |?????? |?????? |?????? |
-----------------------------------
?
Note: rule based optimization
