我在代码中遇到了一些麻烦。我一直在尝试此网站上所有可能的解决方案，但没有任何效果。我似乎无法理解可能是什么问题。
我尝试过的解决方案的链接：
Spring Boot，JPA错误：“通过JDBC语句执行DDL错误”
系统配置：Ubuntu 16.04 MySQL 8
2018-11-06 12:38:52.273 INFO 16491 --- [ main] org.hibernate.dialect.Dialect : HHH000400: Using dialect: org.hibernate.dialect.MySQL5InnoDBDialect
Hibernate: create table outputmessages (id integer not null, from varchar(255), message varchar(255), time datetime, topic varchar(255), primary key (id)) engine=InnoDB
2018-11-06 12:38:53.117 WARN 16491 --- [ main] o.h.t.s.i.ExceptionHandlerLoggedImpl : GenerationTarget encountered exception accepting command : Error executing DDL via JDBC Statement
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL via JDBC Statement
at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlString(AbstractSchemaMigrator.java:559) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlStrings(AbstractSchemaMigrator.java:504) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at …