MySQL ORDER BY ASC 并显示 NULL 值到底部?


为此,将 CASE 语句与 ORDER BY 结合使用。让我们首先创建一个表 -

mysql> create table DemoTable1937
   (
   Name varchar(20)
   );
Query OK, 0 rows affected (0.00 sec)

使用 insert 命令在表中插入一些记录 -

mysql> insert into DemoTable1937 values('Chris');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1937 values(NULL);
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1937 values('Adam');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1937 values('John');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1937 values('');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1937 values(NULL);
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1937 values('Bob');
Query OK, 1 row affected (0.00 sec)

使用 select 命令在表中显示所有记录 -

mysql> select * from DemoTable1937;

这将产生以下输出 -

+-------+
| Name  |
+-------+
| Chris |
| NULL  |
| Adam  |
| John  |
|       |
| NULL  |
| Bob   |
+-------+
7 rows in set (0.00 sec)

以下是 ORDER BY ASC 并显示 NULL 值到底部的查询

mysql> select * from DemoTable1937
   order by case when Name IS NULL then 100
   when Name='' then 101
   else 103
   end desc
   ,
   Name asc;

这将产生以下输出 -

+-------+
| Name  |
+-------+
| Adam  |
| Bob   |
| Chris |
| John  |
|       |
| NULL  |
| NULL  |
+-------+
7 rows in set (0.00 sec)

更新于: 2019-12-30

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