学习数据库的记录.

1.

LOAD DATA LOCAL INFILE '/Users/cancer/Desktop/pet.txt' INTO TABLE pet LINES TERMINATED BY '\r\n';

用于将pet.txt的内容写入文档,pet内容如下

Whistler        Gwen    bird    \N      1997-12-09

注:每个字段的值应该用tab隔开,否则一行信息将录入第一个字段值.

2.DISTINCT
distinct 关键字可以将选择的字段去重复.
eg.

select  owner from pet

+-------+
| owner |
+-------+
| NULL |
| NULL |
| NULL |
| NULL |
| NULL |
| Diane |
| Diane |
| Gwen |
+-------+

select  distinct owner from pet

+-------+
| owner |
+-------+
| NULL |
| Diane |
| Gwen |
+-------+

3.REGEXP
REGEXP 表示使用正则表达式去匹配
eg.

select name from pet where name regexp '^.{8}$'

匹配名字为8个字符的值.