Analysis on sorting of null values in mysql _ MySQL

Analysis on sorting of null values in mysql bitsCN.com

Analysis on sorting of null values in mysql

Table t_user:

Name age

Zhangsan 1

Lisi NULL

Wangwu 2

Run the following SQL statement:

SQL code

Select * from t_user order by age;

Name age

Lisi NULL

Zhangsan 1

Wangwu 2

In fact, we want to put records without age at the end. we can

SQL code

Select * from t_user order by age is null, age;

Name age

Zhangsan 1

Wangwu 2

Lisi NULL

Why? It can be understood as follows:

SQL code

Select * from t_user order by age is null, age;

It is equivalent:

SQL code

Select * from (select name, age, (age is null) as isnull from t_user) as foo order by isnull, age;

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