이응기역

C:\jee-2020-092\eclipse>eclipse -clearPersistedState

Entity 쪽 컬럼에 값이 유일해질 수 있도록 컬럼에 @Id 추가

The JPA Id does not always have to match the database table primary key constraint, nor is a primary key or a unique constraint required.

https://en.wikibooks.org/wiki/Java_Persistence/Identity_and_Sequencing#No_Primary_Key

https://docs.spring.io/spring-data/commons/docs/current/api/org/springframework/data/repository/CrudRepository.html

long -> Integer

int -> Integer

https://stackoverflow.com/questions/3154582/why-do-i-get-a-null-value-was-assigned-to-a-property-of-primitive-type-setter-o

SELECT 'a' = 'A'; -- 1
SELECT BINARY 'a' = 'A'; -- 0

(dev.mysql.com/doc/refman/5.7/en/cast-functions.html#operator_binary)

date -d '10 hour ago' '+%Y-%m-%d %H'

:g/^$/d

SELECT * FROM BATCH_INFO20 WHERE FIND_IN_SET(DATE_FORMAT(NOW(), '%H'), EXEC_HOURS);

(stackoverflow.com/questions/18710921/mysql-find-in-set-with-array-string)

with recursive T as ( select 'a,b,c,d,e,f' as items), N as ( select 1 as n union select n + 1 from N, T where n <= length(items) - length(replace(items, ',', ''))) select distinct substring_index(substring_index(items, ',', n), ',', -1) group_name from N, T

(stackoverflow.com/questions/17942508/sql-split-values-to-multiple-rows)