redis 基本命令

redis是一个键值对数据库，可以通过redis-cli启动命令行工具，命令可以大小写混写，建议都大写。

Redis Strings:

set key value [EX seconds] [PX milliseconds] [NX|XX]

get key

INCR key

INCRBY key increment

DECR key

DECRBY key decrement

//设置新值，并返回原值
GETSET

MSET key value [key value ...]
MGET key [key ...]


exists key [key ...]

DEL key [key ...]

type key 

expire key seconds

ttl key

Redis lists基于Linked Lists实现。

LPUSH key value [value ...]
RPUSH key value [value ...]
rpop key
lpop key

// -1 代表尾部元素
lrange key start stop  
LLEN key

Redis hash

hset key field value
hmset key field value [field value ...]
hget key field
hmget key field [field ...]

hgetall key

// 居然只有加没有减
hincrby key field increment


Redis Set 是 String 的无序排列

sadd key member [member ...]
smembers key
sismember key member
spop key [count]

// 获取set的数量
scard key

// 它获取不同 set 的交集
sinter key [key ...]

// 用于对多个集合取并集，并把结果存入另一个 set 中
SUNIONSTORE destination key [key ...]

Redis Sorted sets

和set一样值唯一，但是需要给每一个值设置一个分数（这里类似hash），按分数排序。规则如下。

• If A and B are two elements with a different score, then A > B if A.score is > B.score.
• If A and B have exactly the same score, then A > B if the A string is lexicographically greater than the B string. A and B strings can’t be equal since sorted sets only have unique elements.

命令：

zadd key [NX|XX] [CH] [INCR] score member [score member ...]

zrange key start stop [WITHSCORES]
zrevrange key start stop [WITHSCORES]

// -inf, inf  可用
zrangebyscore key min max [WITHSCORES] [LIMIT offset count]

// remove data between min and max 
zremrangebyscore key min max

//  ask what is the position of an element 
zrank key member

exicographical scores 字典顺序分数,当sorted set 的分数相同时，采用字典序。

zrangebylex key min max [LIMIT offset count]