意外查询成功

SELECT COUNT (*)
  FROM rps2_workflow
 WHERE     workflow_added > TO_DATE ('01.09.2011', 'dd.mm.yyyy')
       AND workflow_finished < TO_DATE ('wtf', 'dd.mm.yyyy')
       AND workflow_status IN (7, 12, 17)
       AND workflow_worker = 159

我预计此查询会失败，因为日期无效，但它返回 0

该查询的计划显示，在第 8 步，无效子句is处理：

8 TABLE ACCESS BY INDEX ROWID TABLE RPS2.RPS2_WORKFLOW Object Instance: 1  Filter Predicates: ("WORKFLOW_STATUS"=7 OR "WORKFLOW_STATUS"=12 OR "WORKFLOW_STATUS"=17) AND SYS_EXTRACT_UTC("WORKFLOW_FINISHED")<SYS_EXTRACT_UTC(TO_DATE('wtf','dd.mm.yyyy'))  Cost: 11  Bytes: 33  Cardinality: 1  CPU Cost: 8 M  IO Cost: 10  Time: 1                     

如果我们注释掉AND workflow_status IN (7, 12, 17)条件 - 那么我们预计会得到ORA-01858: a non-numeric character was found where a numeric was expected

如果我们注释掉AND workflow_finished < TO_DATE ('wtf', 'dd.mm.yyyy')然后我们得到符合条件的记录数量 (> 0)

这怎么可能？

UPD:

提示/*+no_index(rps2_workflow) */不会改变任何东西（而在计划中我们看到执行了全扫描）

SELECT STATEMENT  ALL_ROWSCost: 254  Bytes: 31  Cardinality: 1  CPU Cost: 34 M  IO Cost: 248  Time: 4       
2 SORT AGGREGATE  Bytes: 31  Cardinality: 1     
    1 TABLE ACCESS FULL TABLE RPS2.RPS2_WORKFLOW Object Instance: 1  Filter Predicates: "WORKFLOW_WORKER"=159 AND ("WORKFLOW_STATUS"=7 OR "WORKFLOW_STATUS"=12 OR "WORKFLOW_STATUS"=17) AND SYS_EXTRACT_UTC("WORKFLOW_ADDED")>SYS_EXTRACT_UTC(TIMESTAMP' 2011-09-01 00:00:00') AND SYS_EXTRACT_UTC("WORKFLOW_FINISHED")<SYS_EXTRACT_UTC(TO_DATE('wtf','dd.mm.yyyy'))  Cost: 254  Bytes: 31  Cardinality: 1  CPU Cost: 34 M  IO Cost: 248  Time: 4  

如果优化器决定不需要评估函数，它就不会，因此函数永远不会抛出异常：

select 1 from dual where 1 = 1 OR to_date('asdasdasd','asdasdasdas') > sysdate ;

         1
----------
         1

仅当该函数实际被求值时才会引发异常：

SQL> select 1 from dual where 1 = 1 AND to_date('asdasd','asdas') > sysdate ;
select 1 from dual where 1 = 1 AND to_date('asdasd','asdas') > sysdate
                                                    *
ERROR at line 1:
ORA-01821: date format not recognized

然而，如果解析器可以决定静态地查询无效 - 因为函数具有错误类型的参数或查询具有无效类型，那么解析器将在优化器对其进行调整之前引发异常：

SQL> select 1 from dual where 1 = 1 or to_date('asdasdasd',0) > sysdate ;
select 1 from dual where 1 = 1 or to_date('asdasdasd',0) > sysdate
                                                         *
ERROR at line 1:
ORA-00932: inconsistent datatypes: expected DATE got NUMBER


SQL> select 1 from dual where 1 = 1 or to_date('asdasdasd','asdasdasdas') > 42 ;
select 1 from dual where 1 = 1 or to_date('asdasdasd','asdasdasdas') > 42
                                                                        *
ERROR at line 1:
ORA-00932: inconsistent datatypes: expected DATE got NUMBER