我可以使用ON语句中的CASE子句加入ORACLE(10g)中的表(或者甚至是where子句,因为它是内连接)

我认为CASE声明在连接条件下工作,但我不确定.但这对你有用吗？

select *
  from table1 a
 where a.cola1 = 'valuea1'
    or (a.cola1 = 'valuea2'
        and Exists(select 1
                     from table2 b
                    where a.cola2 = b.colb2
                      and b.colb3 = 'valueb3'
                   )
        )

编辑:这不会简单地工作吗？

select a.*
  from table1 a
  Left Outer Join table2 b On (a.cola2 = b.colb2)
 where a.cola1 = 'valuea1'
    or (a.cola1 = 'valuea2' and b.colb3 = 'valueb3')