クエリでの時間関数の使用

obclient> SELECT NOW(),DATE_FORMAT(NOW(),"%Y/%M/%D %T") new_time;
+---------------------+-------------------------+
| NOW()               | new_time                |
+---------------------+-------------------------+
| 2022-03-08 18:26:31 | 2022/March/8th 18:26:31 |
+---------------------+-------------------------+
1 row in set

obclient> SET @dt = NOW();
Query OK, 0 rows affected

obclient> SELECT @dt
    , EXTRACT(YEAR FROM @dt)    d_year
    , EXTRACT(MONTH FROM @dt)   d_month
    , EXTRACT(week FROM @dt)    d_week
    , EXTRACT(DAY FROM @dt)     d_day
    , EXTRACT(HOUR FROM @dt)    d_hour
    , EXTRACT(MINUTE FROM @dt)  d_min
    , EXTRACT(SECOND FROM @dt)  d_second
    , EXTRACT(year_month FROM @dt)  d_year_month
    , EXTRACT(hour_minute FROM @dt) d_hour_min
\G

*************************** 1. row ***************************
         @dt: 2022-03-08 18:28:53
      d_year: 2022
     d_month: 3
      d_week: 10
       d_day: 8
      d_hour: 18
       d_min: 28
    d_second: 53
d_year_month: 202203
  d_hour_min: 1828
1 row in set

obclient> SET @dt = NOW();
Query OK, 0 rows affected

obclient> SELECT @dt
    , DATE_ADD(@dt, INTERVAL 1 DAY )        t1
    , DATE_ADD(@dt, INTERVAL 1 HOUR )       t2
    , DATE_ADD(@dt, INTERVAL -10 MINUTE )   t3
    , DATE_ADD(@dt, INTERVAL -1 MONTH )     t4
    , DATE_ADD(@dt, INTERVAL 1 YEAR )       t5
\G

*************************** 1. row ***************************
@dt: 2022-03-08 18:28:53
 t1: 2022-03-09 18:28:53
 t2: 2022-03-08 19:28:53
 t3: 2022-03-08 18:18:53
 t4: 2022-02-08 18:28:53
 t5: 2023-03-08 18:28:53
1 row in set