描述 DELETE 從指明的表里刪除滿足 WHERE condition?。l件)的行. 如果 condition?。╓HERE 子句)不存在,效果是刪除表中所有行.結(jié)果是一個(gè)有效的空表.
小技巧: TRUNCATE 是一個(gè) Postgres 擴(kuò)展,它提供一個(gè)更快的從表中刪除所有行的機(jī)制。 要對(duì)表進(jìn)行修改,你必須有寫權(quán)限,同樣也必須有讀表的權(quán)限,這樣才能對(duì)符合 condition (條件)的值進(jìn)行讀取操作. 用法 刪除所有電影(films)但不刪除音樂(musicals): DELETE FROM films WHERE kind <> 'Musical'; SELECT * FROM films;
code | title | did | date_prod | kind | len -------+---------------------------+-----+------------+---------+------- UA501 | West Side Story | 105 | 1961-01-03 | Musical | 02:32 TC901 | The King and I | 109 | 1956-08-11 | Musical | 02:13 WD101 | Bed Knobs and Broomsticks | 111 | | Musical | 01:57 (3 rows) 清空表 films: DELETE FROM films; SELECT * FROM films;
code | title | did | date_prod | kind | len ------+-------+-----+-----------+------+----- (0 rows) 兼容性 SQL92 SQL92 允許定位的 DELETE?。▌h除)語句: DELETE FROM table WHERE CURRENT OF cursor 這里 cursor 表示一個(gè)打開的游標(biāo).Postgres 里交互式游標(biāo)是只讀的.