SQLite 날짜

-- 날짜 자동등록
CREATE TABLE IF NOT EXISTS tablename (
	[idx] INTEGER PRIMARY KEY AUTOINCREMENT,
	[content] TEXT,
	[send_state] INTEGER,
	[send_date] DATETIME DEFAULT (DATETIME('now', 'localtime'))
);

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-- 2021-10-24 19:45:00 기준
-----------------------------


-- 국제표준시
SELECT DATETIME('now');  --> UTC(국제 표준시)

-- 한국표준시
SELECT DATETIME('now', 'localtime');  --> KST(한국 표준시, UCT+09:00)

-- 날짜만
SELECT DATE('now', 'localtime'); --> Result: KST 2021-10-24  -->  Result: 20211024-194500

-- 날짜포맷 변경
SELECT strftime('%Y%m%d_%H%M%S', DATETIME('now', 'localtime')) as KSTCustom  --> Result: 20211024_194500

-- 날짜검색용
SELECT DATETIME('now', '+1 year', 'localtime');  -->  Result: 2022-10-24 19:45:00
SELECT DATETIME('now', '+1 month', 'localtime');  -->  Result: 2021-11-24 19:45:00
SELECT DATETIME('now', '+1 day', 'localtime');  -->  Result: 2021-10-25 19:45:00
SELECT DATETIME('now', '+1 hour', 'localtime');  -->  Result: 2021-10-24 20:45:00
SELECT DATETIME('now', '+1 minutes', 'localtime'); -->  Reuslt: 2021-10-24 19:46:00