redis-sort命令

排序

SORT

sort命令的格式：sort key [BY pattern] [LIMIT start count] [GET pattern] [ASC|DESC] [ALPHA] [STORE dstkey]

用来对列表类型、集合类型、有序集合类型键类型进行排序；默认是按照数值类型排序的，并且按照两个元素的双精度浮点数类型值进行比较

127.0.0.1:6379> lpush listsort 1 5 2 6 9
(integer) 5
127.0.0.1:6379> sort listsort
1) "1"
2) "2"
3) "5"
4) "6"
5) "9"
#如果时字符类型会报错
127.0.0.1:6379> lrange list 0 4
1) "a1"
2) "b"
3) "a"
127.0.0.1:6379> sort list
(error) ERR One or more scores can't be converted into double

如果时字符串值并且是按照字典顺序排序，可以使用alpha参数修饰

127.0.0.1:6379> sort list  ALPHA
1) "a"
2) "a1"
3) "b"

[BY pattern]

除了可以按集合元素自身值（数字，字母）排序外，还可以将集合元素内容按照给定pattern组合成新的key，并按照新key中对应的内容进行排序。

#根据自身的key排序
127.0.0.1:6379> lrange mylist 0 4
1) "a4"
2) "a2"
3) "a3"
4) "a1"
127.0.0.1:6379> sort mylist by a* desc
1) "a4"
2) "a3"
3) "a2"
4) "a1"
#根据外部的key进行排序
127.0.0.1:6379> lrange mylist1 0 -1
1) "4"
2) "2"
3) "1"
4) "3"
127.0.0.1:6379> mget a1 a2 a3 a4
1) "a1"
2) "a2"
3) "a3"
4) "a4"
127.0.0.1:6379> sort mylist1 by a* alpha 
1) "1"
2) "2"
3) "3"
4) "4"

[GET pattern]

从上面的实例来看，sort通过外部的key a1,a2,a3,a4 对mylist1进行了排序，那么也可以通过get 去获取指定pattern作为新key去获取值

127.0.0.1:6379> sort mylist1 by a* get a* alpha 
1) "a1"
2) "a2"
3) "a3"
4) "a4"

在get中还有特殊的符号#，表示获取原始集合

127.0.0.1:6379> sort mylist1 by a* get a* get # alpha 
1) "a1"
2) "1"
3) "a2"
4) "2"
5) "a3"
6) "3"
7) "a4"
8) "4"

还有在hash类型中的 ->符号

127.0.0.1:6379> hset user_1 name xiaozhang
(integer) 1
127.0.0.1:6379> hset user_2 name xiaoliu
(integer) 1
127.0.0.1:6379> hset user_3 name xiaowang
(integer) 1
127.0.0.1:6379> hset user_4 name xiaowu
(integer) 1
127.0.0.1:6379> lrange mylist1 0 3
1) "4"
2) "2"
3) "1"
4) "3"
127.0.0.1:6379> sort mylist1 get user_*->name
1) "xiaozhang"
2) "xiaoliu"
3) "xiaowang"
4) "xiaowu"
127.0.0.1:6379> sort mylist1 get user_*->name desc
1) "xiaowu"
2) "xiaowang"
3) "xiaoliu"
4) "xiaozhang"

[LIMIT offset count]

限定排序后的返回结果

127.0.0.1:6379> sort mylist1 get user_*->name desc
1) "xiaowu"
2) "xiaowang"
3) "xiaoliu"
4) "xiaozhang"
127.0.0.1:6379> sort mylist1 get user_*->name limit 0 2 desc
1) "xiaowu"
2) "xiaowang"

[STORE dstkey]

将排序后的结果保存起来，保存数据类型的是list类型

127.0.0.1:6379> sort mylist1 get user_*->name limit 0 2 desc
1) "xiaowu"
2) "xiaowang"
127.0.0.1:6379> sort mylist1 get user_*->name limit 0 2 desc store sortresult
(integer) 2
127.0.0.1:6379> lrange sortresult 0 2
1) "xiaowu"
2) "xiaowang"

hsah中使用get和by

127.0.0.1:6379> lrange mylist1 0 3
1) "4"
2) "2"
3) "1"
4) "3"
127.0.0.1:6379> hmset hash:1 name zhang age 18
OK
127.0.0.1:6379> hmset hash:2 name zhao age 19
OK
127.0.0.1:6379> hmset hash:3 name qian age 15
OK
127.0.0.1:6379> hmset hash:4 name sun age 20
OK
127.0.0.1:6379> sort mylist1 by hash:*->age desc
1) "4"
2) "2"
3) "1"
4) "3"
127.0.0.1:6379> sort mylist1 by hash:*->age desc get hash:*->age
1) "20"
2) "19"
3) "18"
4) "15"
127.0.0.1:6379> sort mylist1 by hash:*->age desc get hash:*->name
1) "sun"
2) "zhao"
3) "zhang"
4) "qian"
127.0.0.1:6379> sort mylist1 by hash:*->age desc get hash:*->name get hash:*->age
1) "sun"
2) "20"
3) "zhao"
4) "19"
5) "zhang"
6) "18"
7) "qian"
8) "15"

性能问题

![image-20200708145223788](

image-20200708145223788.png)