时间间隔表达式
语法： INTERVAL EXPR UNIT
说明：EXPR表示数值，UNIT说明符用于解释数值的单位，如HOUR、DAY、WEEK等。关键字INTERVAL和说明符不区分大小写。
时间间隔表达式中UNIT的取值范围如下表1所示，允许任何标点符号分隔EXPR格式。表1中显示的是建议的分隔符。
INTERVAL表达式仅在sql_compatibility = 'MYSQL'，且参数b_format_version值为5.7、b_format_dev_version值为s1时，才支持上述功能。
UNIT取值范围 |
预期EXPR格式 |
|---|---|
MICROSECOND |
MICROSECONDS |
SECOND |
SECONDS |
MINUTE |
MINUTES |
HOUR |
HOURS |
DAY |
DAYS |
WEEK |
WEEKS |
MONTH |
MONTHS |
QUARTER |
QUARTERS |
YEAR |
YEARS |
SECOND_MICROSECOND |
'SECOND_MICROSECOND' |
MINUTE_MICROSECOND |
'MINUTES:SECONDS.MICROSECONDS' |
MINUTE_SECOND |
'MINUTES:SECONDS' |
HOUR_MICROSECOND |
'HOURS:MINUTES:SECONDS.MICROSECONDS' |
HOUR_SECOND |
'HOURS:MINUTES:SECONDS' |
HOUR_MINUTE |
'HOURS:MINUTES' |
DAY_MICROSECOND |
'DAYS HOURS:MINUTES:SECONDS.MICROSECONDS' |
DAY_SECOND |
'DAYS HOURS:MINUTES:SECONDS' |
DAY_MINUTE |
'DAYS HOURS:MINUTES' |
DAY_HOUR |
'DAYS HOURS' |
YEAR_MONTH |
'YEAR_MONTH' |
示例：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 |
gaussdb=# SELECT DATE_ADD('2018-05-01', INTERVAL 1 DAY); date_add ------------ 2018-05-02 (1 row) gaussdb=# SELECT DATE_SUB('2018-05-01', INTERVAL 1 YEAR); date_sub ------------ 2017-05-01 (1 row) gaussdb=# SELECT DATE'2023-01-10' - INTERVAL 1 DAY; ?column? --------------------- 2023-01-09 00:00:00 (1 row) gaussdb=# SELECT DATE'2023-01-10' + INTERVAL 1 MONTH; ?column? --------------------- 2023-02-10 00:00:00 (1 row) |
