application.properties

# DB setup
spring.datasource.url=jdbc:mysql://localhost:3306/myblog?useSSL=false&characterEncoding=UTF-8&serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=비번

하이버네이트 설정(개발 초기용)

# Hibernate properties
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5InnoDBDialect

# Hibernate ddl auto (create, create-drop, validate, update)
spring.jpa.hibernate.ddl-auto = update

에러없이 실행 확인

참고
https://dololak.tistory.com/465
https://smpark1020.tistory.com/140?category=857916