mysql> SELECT * FROM pet; +----------+--------+---------+------+------------+------------+ | name | owner | species | sex | birth | death | +----------+--------+---------+------+------------+------------+ | Fluffy | Harold | cat | f | 1993-02-04 | NULL | | Claws | Gwen | cat | m | 1994-03-17 | NULL | | Buffy | Harold | dog | f | 1989-05-13 | NULL | | Fang | Benny | dog | m | 1990-08-27 | NULL | | Bowser | Diane | dog | m | 1979-08-31 | 1995-07-29 | | Chirpy | Gwen | bird | f | 1998-09-11 | NULL | | Whistler | Gwen | bird | NULL | 1997-12-09 | NULL | | Slim | Benny | snake | m | 1996-04-29 | NULL | | Puffball | Diane | hamster | f | 1999-03-30 | NULL | +----------+--------+---------+------+------------+------------+
如果你想要浏览整个表,可以使用这种形式的SELECT,例如,刚刚装载了初始数据集以后。也有可能你想到Bowser的生日看起来不很对。查阅你原来的家谱,你发现正确的出生年是1989,而不是1979。
至少有两种修正方法:
· 编辑文件“pet.txt”改正错误,然后使用DELETE和LOAD DATA清空并重新装载表:
· mysql> DELETE FROM pet; · mysql> LOAD DATA LOCAL INFILE 'pet.txt' INTO TABLE pet;
然而, 如果这样操做,必须重新输入Puffball记录。
· 用一个UPDATE语句仅修正错误记录:
· mysql> UPDATE pet SET birth = '1989-08-31' WHERE name = 'Bowser';
UPDATE只更改有问题的记录,不需要重新装载数据库表。