mysql“Everyderivedtablemusthaveitsownalias”出现错误如何解决办法

mysql Every derived table must have its own alias错误解决办法

Every derived table must have its own alias

这句话的意思是说每个派生出来的表都必须有一个自己的别名

一般在多表查询时，会出现此错误。

因为，进行嵌套查询的时候子查询出来的的结果是作为一个派生表来进行上一级的查询的，所以子查询的结果必须要有一个别名

把MySQL语句改成：select count(*) from (select * from ……) as total;

问题就解决了，虽然只加了一个没有任何作用的别名total，但这个别名是必须的

select name1 name, Java, jdbc, hibernate,total
 from (select sc1.name name1, sc1.mark java
  from student_course2 sc1
  where sc1.course='java') as a,
  (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;
 

结果正确：

+----------+------+------+-----------+-------+
| 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)

感谢阅读，希望能帮助到大家，谢谢大家对本站的支持！

到此这篇关于mysql“Everyderivedtablemusthaveitsownalias”出现错误如何解决办法就介绍到这了。抬起一只脚，身倾后方击球最要不得——击球无力，不能迅速回防，予敌可乘之机，会闪腰，姿势也难看。更多相关mysql“Everyderivedtablemusthaveitsownalias”出现错误如何解决办法内容请查看相关栏目，小编编辑不易，再次感谢大家的支持！