MySQL encounters an error similar to "Everyderivedtablemusthaveitsownalias"

MySQL encounters ldquo; Everyderivedtablemusthaveitsownaliasrdquo; similar error description

MySQL encounters ldquo; Every derived table must have its own aliasrdquo; similar error description

Every derived table must have its own alias

This statement means that each derived table must have its own Alias.

This error occurs when multiple tables are queried.

Because, when performing nested queries, the results of the subquery are used as a derived table to perform the query at the upper level. Therefore, the subquery results must have an alias.

Change the MySQL statement to select count (*) from (select * from ......) As total;

The problem is solved. Although only one alias "total" is added, this alias is required.

Select name1 name, java, jdbc, hibernate, total
From (select sc1.name name1, sc1.mark java
From student_course2 sc1
Where sc1.course = 'java') as,
(Select sc2.name name2, sc2.mark jdbc
From student_course2 sc2
Where sc2.course = 'jdbc ') as B,
(Select sc3.name name3, sc3.mark hibernate
From student_course2 sc3
Where sc3.course = 'hibernate ') as c,
(Select sc4.name name4, sum (sc4.mark) total
From student_course2 sc4 group by sc4.name) as d
Where name1 = name2 and name2 = name3 and name3 = name4 order by total ASC;

The result is correct:

+ ---------- + ------ + ----------- + ------- +
| Name | java | jdbc | hibernate | total |
+ ---------- + ------ + ----------- + ------- +
| Wangwu | 40 | 30 | 20 | 90 |
| Lisi | 70 | 60 | 50 | 180 |
| Zhangsan | 100 | 90 | 80 | 270 |
+ ---------- + ------ + ----------- + ------- +
3 rows in set (0.02 sec)

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