sql - Oracle - 按列排序，最后一个位置为 NULL 值

Question

我Order by用于记录排序。我想在每次排序的最后一个位置选择 NULL 记录。例如。

ASC - {1,2,3,4,5,6,7,NULL,NULL,NULL} 
DESC - {7,6,5,4,3,2,1,NULL,NULL,NULL}

如何在 Oracle 查询中执行此操作？

Answer 1

您的 order by 子句应如下所示：

描述

order by <field_name> desc nulls last;

升序

order by <field_name> asc nulls last;

Answer 2

基本 MySql 查询和基于 Yii2 的代码：

Basic Query in MySql:

SELECT *, IF(cloumn_name IS NULL, 1, 0) as cloumn_name_alias FROM `table_name` WHERE 1 ORDER BY cloumn_name_alias, cloumn_name ASC;

For Yii2 Framework:

$dataProvider = new ActiveDataProvider([
            'query' => $query,
            'sort' => [
                'defaultOrder' => [
                    'position_alias' => SORT_ASC,
                    'position'       => SORT_ASC,
                ],
                'attributes' => [
                    'position_alias',
                    'position',
                ]
            ]
        ]);

Answer 3

升压 -

ORDER BY NVL(field, 10000000);  <-- a maximum big constant here

DESC -

ORDER BY NVL(field, 0) DESC;