redis HINCRBY command

incr

increase increase; increase increase; increase increase; increase increase

by

英[ baɪ] 美[baɪ]

prep.beside...;expression method;due to;passing through

adv.passing;expressing retention or preservation; short visit

redis HINCRBY commandsyntax

Function: Add increment to the value of field field in hash table key.

Syntax: HINCRBY key field increment

Explanation: The increment can also be a negative number, which is equivalent to subtracting a given field. If key does not exist, a new hash table is created and the HINCRBY command is executed. If the field field does not exist, the value of the field is initialized to 0 before executing the command. Executing the HINCRBY command on a field that stores string values ​​will cause an error. The value of this operation is limited to a 64-bit signed number representation.

Available versions: >= 2.0.0

Time complexity: O(1)

Return: After executing the HINCRBY command, the value of the field field in the hash table key.

redis HINCRBY commandexample

# increment 为正数
redis> HEXISTS counter page_view    # 对空域进行设置
(integer) 0
redis> HINCRBY counter page_view 200
(integer) 200
redis> HGET counter page_view
"200"
# increment 为负数
redis> HGET counter page_view
"200"
redis> HINCRBY counter page_view -50
(integer) 150
redis> HGET counter page_view
"150"
# 尝试对字符串值的域执行HINCRBY命令
redis> HSET myhash string hello,world       # 设定一个字符串值
(integer) 1
redis> HGET myhash string
"hello,world"
redis> HINCRBY myhash string 1              # 命令执行失败，错误。
(error) ERR hash value is not an integer
redis> HGET myhash string                   # 原值不变
"hello,world"