MySQL函式提取字串中的數字
阿新 • • 發佈:2019-02-05
實現:用 MySQL 函式提取形如“http://www.xxx.com/hotel/detail/826457”中的數字部分
MySQL 版本:5.7
思路:
① 把字串 str0 反轉得 str1
② - str1(字元型轉整型) 得 str2
③ - str2 得 str3,反轉 str3 得 str4
④ 考慮到 str0 中會含有 '^.*[1-9]+0{n}$' 格式的資料,要擷取 str0 中自 str4 位置開始到 str0 結束的子字串作為最終提取結果
相關 sql:
mysql> use test Database changed mysql> show tables; Empty set (0.00 sec) mysql> create table test_reverse ( -> id int unsigned not null auto_increment, -> url varchar(255) not null default '', -> primary key (id) -> ) engine = innodb default charset = utf8 collate = utf8_unicode_ci; Query OK, 0 rows affected (0.34 sec) mysql> insert into test_reverse values (null, 'http://www.zpcode.com/826457'),(null, 'http://zpcode. org/390'); Query OK, 2 rows affected (0.11 sec) Records: 2 Duplicates: 0 Warnings: 0 mysql> select * from test_reverse; +----+------------------------------+ | id | url | +----+------------------------------+ | 1 | http://www.zpcode.com/826457 | | 2 | http://zpcode.org/390 | +----+------------------------------+ 2 rows in set (0.00 sec) mysql> alter table test_reverse add number_in_string int unsigned not null; Query OK, 0 rows affected (0.65 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> select * from test_reverse; +----+------------------------------+------------------+ | id | url | number_in_string | +----+------------------------------+------------------+ | 1 | http://www.zpcode.com/826457 | 0 | | 2 | http://zpcode.org/390 | 0 | +----+------------------------------+------------------+ 2 rows in set (0.00 sec) mysql> update test_reverse set number_in_string = reverse(-(-reverse(url))); Query OK, 2 rows affected (0.12 sec) Rows matched: 2 Changed: 2 Warnings: 0 mysql> select * from test_reverse; +----+------------------------------+------------------+ | id | url | number_in_string | +----+------------------------------+------------------+ | 1 | http://www.zpcode.com/826457 | 826457 | | 2 | http://zpcode.org/390 | 39 | +----+------------------------------+------------------+ 2 rows in set (0.00 sec) mysql> update test_reverse set number_in_string = substring(url, instr(url, number_in_string)); Query OK, 1 row affected (0.09 sec) Rows matched: 2 Changed: 1 Warnings: 0 mysql> select * from test_reverse; +----+------------------------------+------------------+ | id | url | number_in_string | +----+------------------------------+------------------+ | 1 | http://www.zpcode.com/826457 | 826457 | | 2 | http://zpcode.org/390 | 390 | +----+------------------------------+------------------+ 2 rows in set (0.00 sec)