ORACLE自定义顺序排序

ORACLE可以借助DECODE函数，自定义顺序排序：

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开发中，常需要将Total放最后，其它项则按其它排序方式（一般按正常的升序），可看作同一列有两种排序方式，那么可以这样：

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;