ORACLE自定義順序排序

ORACLE可以借助DECODE函數，自定義順序排序：

select * from (
    select 'Nick' as item from dual
    union all
    select 'Viki' as item from dual
    union all
    select 'Glen' as item from dual
    union all
    select 'Robin' as item from dual
    union all
    select 'Total' as item from dual
) pre_tab
order by decode(item, 'Viki', 1, 'Glen', 2, 'Robin', 3, 'Nick', 4, 'Total', 99);

 

另外，在Report開發中，常需要將Total放最后，其它項則按其它排序方式（一般按正常的升序），可看作同一列有兩種排序方式，那么可以這樣：

select * from (
    select 'Nick' as item from dual
    union all
    select 'Viki' as item from dual
    union all
    select 'Glen' as item from dual
    union all
    select 'Robin' as item from dual
    union all
    select 'Total' as item from dual
) pre_tab
order by decode(item, 'Total', 2, 1), item;