Question

是否可以调整以下查询？我可以不使用减号运算符来写吗？

typeof(Genes).GetFields(BindingFlags.NonPublic);

Answer 1

您可以使用LEFT JOIN代替MINUS：

SELECT m.table_owner ||'.' ||m.table_name AS table_name 
FROM ALL_TAB_MODIFICATIONS m
LEFT OUTER JOIN dba_objects o 
    ON m.table_owner = o.owner 
    AND m.table_name = o.object_name 
    AND o.created >= sysdate -80 
    AND o.object_type = 'TABLE'
WHERE TIMESTAMP >= sysdate -80 
    AND m.table_owner IN ('AXIOM_DATA','AXIOM_DATA2','AXIOM_META','AXIOM_META2') 
    AND m.table_name LIKE 'RPTD_%'
    AND o.table_name IS NULL

连接的右部分必须为空

Answer 2

您可以尝试将其转换为NOT EXISTS查询。如果不需要created >= SYSDATE - 80，则可以查询较小的表dba_tables而不是dba_objects，这意味着查询可以写为

SELECT table_owner || '.' || table_name AS table_name
    FROM all_tab_modifications m
     WHERE timestamp >= SYSDATE - 80 AND table_owner IN (
          'AXIOM_DATA',
          'AXIOM_DATA2',
          'AXIOM_META',
          'AXIOM_META2'
     ) AND table_name LIKE 'RPTD_%' AND NOT EXISTS (
          SELECT 1
          FROM dba_tables t
          WHERE t.owner = m.table_owner AND t.table_name = m.table_name
     );

但是，如果您仍然希望进行比较，则必须在NOT EXISTS中与dba_objects一起适当使用条件

SELECT table_owner || '.' || table_name AS table_name
     FROM all_tab_modifications m
     WHERE timestamp >= SYSDATE - 80 AND table_owner IN (
          'AXIOM_DATA',
          'AXIOM_DATA2',
          'AXIOM_META',
          'AXIOM_META2'
     ) AND table_name LIKE 'RPTD_%' AND NOT EXISTS (
          SELECT 1
            FROM dba_objects t
          WHERE t.owner = m.table_owner AND t.object_name = m.table_name 
          AND t.object_type ='TABLE'
          AND t.created  >= SYSDATE - 80 
     );

Answer 3

我没有Oracle数据库可以检查索引或解释计划，但是...

 SELECT owner || '.' || object_name AS table_name
 FROM dba_objects
 WHERE created >= SYSDATE - 80 AND owner IN (
   'AXIOM_DATA',
   'AXIOM_DATA2',
   'AXIOM_META',
   'AXIOM_META2'
 ) AND object_name LIKE 'RPTD_%' 
 AND object_type != 'TABLE'

调整以下查询

3 个答案: