当分组记录具有多个相匹配的字符串时,MySQL Select 怎么办?
对此可以使用正则表达式。我们首先创建一个表 -
mysql> create table DemoTable ( ProductId int NOT NULL AUTO_INCREMENT PRIMARY KEY, ProductName varchar(20) ); Query OK, 0 rows affected (0.19 sec)
使用 insert 命令在表中插入一些记录 -
mysql> insert into DemoTable(ProductName) values('Product-1');
Query OK, 1 row affected (0.05 sec)
mysql> insert into DemoTable(ProductName) values('Product2');
Query OK, 1 row affected (0.06 sec)
mysql> insert into DemoTable(ProductName) values('Product1');
Query OK, 1 row affected (0.04 sec)
mysql> insert into DemoTable(ProductName) values('Product-3');
Query OK, 1 row affected (0.05 sec)
mysql> insert into DemoTable(ProductName) values('Product3');
Query OK, 1 row affected (0.05 sec)
mysql> insert into DemoTable(ProductName) values('Product-4');
Query OK, 1 row affected (0.09 sec)
mysql> insert into DemoTable(ProductName) values('Product4');
Query OK, 1 row affected (0.05 sec)使用 select 语句从表中显示所有记录 -
mysql> select *from DemoTable;
这将产生以下输出 -
+-----------+-------------+ | ProductId | ProductName | +-----------+-------------+ | 1 | Product-1 | | 2 | Product2 | | 3 | Product1 | | 4 | Product-3 | | 5 | Product3 | | 6 | Product-4 | | 7 | Product4 | +-----------+-------------+ 7 rows in set (0.00 sec)
以下是具有多个匹配字符串的分组记录的查询 -
mysql> select *from DemoTable where ProductName regexp 'Product[1234].*';
这将产生以下输出 -
+-----------+-------------+ | ProductId | ProductName | +-----------+-------------+ | 2 | Product2 | | 3 | Product1 | | 5 | Product3 | | 7 | Product4 | +-----------+-------------+ 4 rows in set (0.00 sec)
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