Clickhouse MAP类型

先照着把表做一个：Map类型：ClickHouse中对动态字段的支持 - 简书 (jianshu.com) 

CREATE TABLE user_game_play
 
(
 
   mid UInt64,
 
   buvid String,
 
   game_play_duration Map(String, UInt32),
 
   log_date String
 
)
 
ENGINE=MergeTree()
 
PARTITION BY log_date
 
ORDER BY mid;

insert into user_game_play values (1, '123', map('wzry',3600, 'FGO', 1800), '2021-11-14');

SELECT game_play_duration['wzry'] AS duration FROM user_game_play

结果

┌─duration─┐
│     3600 │
└──────────┘

从GitHub clickhouse上的回复上知道，map是根据线性数组实现的，性能上没有array强。clickhouse-issues@23299

 

函数

tuple-map-functions | ClickHouse Docs