Mysql 包含空值的SQL排序

我尝试了以下查询，以便与表中的空条目一起排序。我需要按书名和书号进行排序

对于升序：

SELECT book_id 
FROM   books 
GROUP  BY book_id 
ORDER  BY CASE 
            WHEN book_id IS NULL THEN 1 
            ELSE 0 
          END, 
          book_id; 

 1 
 2 
 NULL

1
2
NULL

预期结果：

对于升序：

SELECT book_id 
FROM   books 
GROUP  BY book_id 
ORDER  BY CASE 
            WHEN book_id IS NULL THEN 1 
            ELSE 0 
          END, 
          book_id; 

 1 
 2 
 NULL

1
2
NULL

对于降序：

SELECT book_id 
FROM   books 
GROUP  BY book_id 
ORDER  BY CASE 
            WHEN book_id IS NULL THEN 1 
            ELSE 0 
          END DESC, 
          book_id; 




 NULL
 1 
 2 

NULL
2
1

预期结果：

对于降序：

SELECT book_id 
FROM   books 
GROUP  BY book_id 
ORDER  BY CASE 
            WHEN book_id IS NULL THEN 1 
            ELSE 0 
          END DESC, 
          book_id; 




 NULL
 1 
 2 

NULL
2
1

---

您还可以将

DESC

排序方向应用于第二个排序列：

SELECT book_id 
FROM   books 
GROUP  BY book_id 
ORDER  BY CASE WHEN book_id IS NULL 
             THEN 1 
             ELSE 0 
          END DESC, 
          book_id DESC; --- !!!

---

如果省略它，默认值是ASC

只需将空值设置为-1，然后根据该值排序。比如说

 SELECT book_id 
FROM   books 
GROUP  BY book_id 
ORDER  BY isnull(book_id,-1) ASC; 

ASC：

描述：

---

您也可以使用以下查询-

用于升序

SELECT book_id 
FROM   books 
GROUP  BY book_id 
ORDER  BY IF(book_id IS NULL,1,0), book_id;

SELECT book_id 
FROM   books 
GROUP  BY book_id 
ORDER  BY IF(book_id IS NULL,0,1), book_id DESC;

用于下降

SELECT book_id 
FROM   books 
GROUP  BY book_id 
ORDER  BY IF(book_id IS NULL,1,0), book_id;

SELECT book_id 
FROM   books 
GROUP  BY book_id 
ORDER  BY IF(book_id IS NULL,0,1), book_id DESC;

---

当book_id为空时，按大小写排序，然后为1或0 end desc，book_id desc

按大小写保存一些键入内容

当book_id为空时，按大小写顺序保存，然后0或1结束，book_id desc

。是否同时查找MySQL和MS SQL Server的代码？（不要标记不直接涉及的产品…）是否为MySQL或MS SQL Server或两者的

isnull（）；这是不是把
NULL
值放在了底部？我错了，我以为我们是关于MSSql的，Felix ASC是正确的，在这个例子中使用你是对的，这将按升序对非NULL
图书id
进行排序。OP希望按降序对其进行排序，顶部为
NULL
值。