MySQL 查询选择一个特定行和另一个随机行?\
mysqlmysqli database
要选择一个特定行和另一个随机行，您可以使用 ORDER BY 和 RAND()。让我们首先创建一个示例表:
mysql> create table oneSpecificRowAndOtherRandom -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Name varchar(20) -> ); Query OK, 0 rows affected (0.72 sec)
下面是使用 insert 命令在表中插入一些记录的查询:
mysql> insert into oneSpecificRowAndOtherRandom(Name) values('Larry');
Query OK, 1 row affected (0.56 sec)
mysql> insert into oneSpecificRowAndOtherRandom(Name) values('Sam');
Query OK, 1 row affected (0.13 sec)
mysql> insert into oneSpecificRowAndOtherRandom(Name) values('Mike');
Query OK, 1 row affected (0.12 sec)
mysql> insert into oneSpecificRowAndOtherRandom(Name) values('Carol');
Query OK, 1 row affected (0.15 sec)
mysql> insert into oneSpecificRowAndOtherRandom(Name) values('Chris');
Query OK, 1 row affected (0.21 sec)
mysql> insert into oneSpecificRowAndOtherRandom(Name) values('Bob');
Query OK, 1 row affected (0.13 sec)
mysql> insert into oneSpecificRowAndOtherRandom(Name) values('David');
Query OK, 1 row affected (0.13 sec)
以下是使用 select 命令显示表中记录的查询:
mysql> select *from oneSpecificRowAndOtherRandom;
这将产生以下输出 −
+----+-------+ | Id | Name | +----+-------+ | 1 | Larry | | 2 | Sam | | 3 | Mike | | 4 | Carol | | 5 | Chris | | 6 | Bob | | 7 | David | +----+-------+ 7 rows in set (0.00 sec)
以下是选择一个特定行和另一个随机行的查询:
mysql> select *from oneSpecificRowAndOtherRandom ORDER BY (Id= 5) DESC, RAND() LIMIT 0,3;
将产生以下输出 −
+----+-------+ | Id | Name | +----+-------+ | 5 | Chris | | 1 | Larry | | 2 | Sam | +----+-------+ 3 rows in set (0.05 sec)
让我们再次运行相同的查询来显示随机记录，因为我们使用了 RAND():
mysql> select *from oneSpecificRowAndOtherRandom ORDER BY (Id= 5) DESC, RAND() LIMIT 0,3;
这将产生以下输出 −
+----+-------+ | Id | Name | +----+-------+ | 5 | Chris | | 2 | Sam | | 4 | Carol | +----+-------+ 3 rows in set (0.00 sec)
