incr

increase increase; increase increase; increase increase; increase increase

by

英[ ba?] 美[ba?]

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

adv.passing;expressing retention or preservation; short visit

redis HINCRBY command syntax

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 command example

# increment 為正數(shù)
redis> HEXISTS counter page_view    # 對空域進(jìn)行設(shè)置
(integer) 0
redis> HINCRBY counter page_view 200
(integer) 200
redis> HGET counter page_view
"200"
# increment 為負(fù)數(shù)
redis> HGET counter page_view
"200"
redis> HINCRBY counter page_view -50
(integer) 150
redis> HGET counter page_view
"150"
# 嘗試對字符串值的域執(zhí)行HINCRBY命令
redis> HSET myhash string hello,world       # 設(shè)定一個字符串值
(integer) 1
redis> HGET myhash string
"hello,world"
redis> HINCRBY myhash string 1              # 命令執(zhí)行失敗，錯誤。
(error) ERR hash value is not an integer
redis> HGET myhash string                   # 原值不變
"hello,world"