---客户端链接工具
clickhouse-client -m -u root -p root
--大小写敏感的
CREATE TEMPORARY TABLE IF NOT EXISTS test.member_new_simple2 ENGINE = Memory
AS SELECT ID,user_id,member_grade,accum_amount from test.member_new;
-- SHOW PROCESSLIST
查询正在进行执行的sql操作
关于 update/delete操作
clickhouse关于update/delete操作是异步后台进行,而且成本很高,所以尽量减少和避免进行update/delete操作
通过 select * from system.mutations 可以判断后台操作进行是否完成
-------------- create --------------------
create TABLE test.test( id Int32,create_date Date ,c2 Nullable(String) )
engine=MergeTree(create_date,id,(c3,c2),8192);
create TABLE test.test2( id Int32,create_date Date ,c2 Nullable(String) )
engine=MergeTree(create_date,id,8192);
--支持联合索引
MergeTree(EventDate, (CounterID, EventDate), 8192)
MergeTree(EventDate, intHash32(UserID), (CounterID, EventDate, intHash32(UserID)), 8192)
CREATE TABLE t (a UInt8) ENGINE = Memory;
split -b 20g table_name.sql user_group
-------------- ALTER--------------------
ALTER查询只支持MergeTree表，。该查询有几个变体。
ALTER TABLE [db].name [ON CLUSTER cluster] ADD|DROP|MODIFY COLUMN
--更改列的类型
alter TABLE test.ontime_wpp_t MODIFY COLUMN TailNum Nullable(String);
alter TABLE test.ontime_wpp_t ADD COLUMN TailNum2 Nullable(String) after Div5TailNum ;
alter TABLE test.ontime_wpp_t drop COLUMN TailNum2;
表变更数据系统监控
select * from system.mutations where is_done = 0 order by create_time desc limit 1;
删除表
drop table cdm_dwd.dwd_ord_car_sharing_df on cluster crm_4shards_1replicas;
select max(ckbizdate) from cdm_dwd.dwd_mkt_coupon_ord_df
变更表名
RENAME TABLE test.ontime_wpp_t to test.ontime_wpp_t2;
集群操作
RENAME TABLE cdm_dwd.dwd_ord_carsh_base_df2 to cdm_dwd.dwd_ord_carsh_base_df on cluster crm_4shards_1replicas;
SET param = value
允许您设置param值，如果指定了全局，则为会话或服务器（全局）设置设置。
在创建全局设置时，设置并不适用于已经运行的会话，包括当前会话。它只会用于新会话。当服务器重新启动时，
使用SET的全局设置就会丢失。要在服务器重新启动后进行设置
OPTIMIZE table test.ontime;
仅支持MergeTree引擎， 用于回收闲置的数据库空间，当表上的数据行被删除时，
所占据的磁盘空间并没有立即被回收，使用了OPTIMIZE TABLE命令后这些空间将被回收，
并且对磁盘上的数据行进行重排
数据导出
在相关节点执行
echo 'select * from test.ads_user_portrait_vertical_df_cls' | curl localhost:8123?database=test -uroot:root -d @- > table_name.sql
2、导入数据，以tab作为分割符：
导入数据库的本机执行：cat table_name.sql | clickhouse-client --query="INSERT INTO database.table_name FORMAT TabSeparated"
cat /root/user_lable_local_mid_cluster.tgz | clickhouse-client --user hadoop --password hadoop --query="INSERT INTO lmmbase.user_lable_local_mid_cluster FORMAT CSV";
cat /home/hadoop/work_wpp/user_label_uid_cluster | clickhouse-client --user hadoop --password hadoop --query="INSERT INTO lmmbase.user_label_uid_cluster FORMAT CSV";
cat /tmp/test_user2| clickhouse-client --user hadoop --password hadoop --query="INSERT INTO lmmbase.test_user2 FORMAT CSV";
-------------- INSERT--------------------
不严格插入数据，没有出现的列自动填充为默认值
INSERT INTO [db.]table [(c1, c2, c3)] VALUES (v11, v12, v13), (v21, v22)
严格插入数据，每一列都必须出现在上面
INSERT INTO [db.]table [(c1, c2, c3)] FORMAT Values (v11, v12, v13), (v21, v22, v23)
cat /tmp/user_point_info | clickhouse-client --query="INSERT INTO test.user_point_info FORMAT CSV";
cat /home/hadoop/ontime | clickhouse-client --query="INSERT INTO test.ontime_wpp FORMAT CSV";
cat /root/wpp5.log | clickhouse-client --query="INSERT INTO test.test FORMAT CSV";
clickhouse-client -m --user hadoop --password hadoop --query="truncate table lmmbase.user_label_uid on cluster crm_4shards_1replicas";
ssh hadoop@dn1 "/bin/bash /home/hadoop/app/otherApp/truncate_user_label_uid_data.sh"
clickhouse-client --query=" alter table test.ads_user_portrait_vertical_df delete where create_time ='2019-10-17' ";
clickhouse-client --query=" alter table default.test_df delete where ckbizdate ='2019-10-17' ";
相关压测，同时执行相关sql，看下机器负载
*/2 * * * * clickhouse-client -m --query="select t_mac,t_type,count(*) cnt from carendpoint_porlog_cls group by t_mac,t_type order by cnt desc limit 100;"
*/2 * * * * clickhouse-client -m --query="select t_mac,count(*) cnt from carendpoint_porlog_cls group by t_mac order by cnt desc limit 100;"
*/2 * * * * clickhouse-client -m --query="select t_type,count(*) cnt from carendpoint_porlog_cls group by t_type order by cnt desc limit 100;"
*/1 * * * * clickhouse-client -m --query="select t_ip,t_type,count(*) cnt from carendpoint_porlog_cls group by t_ip,t_type order by cnt desc limit 100;" >> /root/wpp1.log
*/1 * * * * clickhouse-client -m --query="select t_ip,count(*) cnt from carendpoint_porlog_cls group by t_ip order by cnt desc limit 100;" >> /root/wpp2.log
*/1 * * * * clickhouse-client -m --query="select event,count(*) cnt from carendpoint_porlog_cls group by event order by cnt desc limit 100;" >> /root/wpp2.log
直接支持hdfs
drop table test_hdfs;
CREATE TABLE test_hdfs
(
rowid Int64,
create_date String,
memo String
)
ENGINE=HDFS('hdfs://gtdata03:8020/input/test2/test2.txt','CSV');
sql 文件执行
clickhouse-client -h 127.0.0.1 -m -d system -q "select * from parts " > test.sql
dn4
clickhouse-client -h 127.0.0.1 -m -d system -q '/home/hadoop/ch.sql' > test.sql
select today()-365;
drop table lmmbase.user_label_uid_hive_cluster on cluster crm_4shards_1replicas;
drop table lmmbase.user_label_uid_hive on cluster crm_4shards_1replicas;
create database on cluster crm_4shards_1replicas;
row_number 函数支持,下面是支持 !!!!!!!!!!!!!
select *,rowNumberInAllBlocks() rn
from(
select id,create_date,c2
from test
order by create_date desc
limit 2 by id
)aa ;
SELECT *, rn +1 -min_rn current, max_rn - min_rn + 1 last FROM (
SELECT *, rowNumberInAllBlocks() rn FROM (
SELECT i_device, i_time
FROM tbl
ORDER BY i_device, i_time
) t
) t1 LEFT JOIN (
SELECT i_device, min(rn) min_rn, max(rn) max_rn FROM (
SELECT *, rowNumberInAllBlocks() rn FROM (
SELECT i_device, i_time
FROM tbl
ORDER BY i_device, i_time
) t
) t GROUP BY i_device
) t2 USING (i_device)
select trainId,ap_mac,
rowNumberInAllBlocks() rn
from carendpoint_usermacprobe
group by trainId,ap_mac
limit 10;
select trainId,ap_mac,
rowNumberInAllBlocks() rn
from carendpoint_usermacprobe
group by trainId,ap_mac
order by trainId desc
limit 3 by trainId;
dn3
select id,create_date,c2,
rowNumberInAllBlocks() rn
from test
group by id,create_date,c2
order by create_date desc
limit 3 by id;
select *,rowNumberInAllBlocks() rn
from(
select id,create_date,c2
from test
group by id,create_date,c2
order by create_date desc
limit 2 by id
)aa ;
insert into test select 11,'2019-07-25','tt5';
select trainId,ap_mac,
ROW_NUMBER() OVER (PARTITION BY trainId order by trainId ) AS row
from carendpoint_usermacprobe limit ;
----------------------delete
删除表的数据，对主键支持的可以，非主键有时数据删除有问题
alter table user_label_uid_hive delete where id = 1000000010002
alter table user_label_uid_hive delete where id = 1000000010002
truncate table ads_user_portrait_vertical_df_cls ON CLUSTER crm_4shards_1replicas;
-- 数据去重
select user_id, order_id, create_time, update_time from unity_order
where create_time> '2018-09-01' order by create_time asc limit 2 by user_id limit 20;
insert into user2( ROWKEY2, AV, IMEI, MAC, CHID, PB, PLAT,UID,PTIME) values
( "20190905", "2.1.6", "54b6aeba8581413ca487eda6caa62a55", "7c:76:68:19:34:16", "NULL22", "HONOR", "2", "tt", "2019-09-05");
,( "20190905_USERID257641565864162599", "1.0.0", "USERID257641565864162599", "other", "other", "iPhone", "3", "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJhY2NvdW50SWQiOiIxMTA0OTQzMTM5Mjg3ODU5MjAwIiwibW9iaWxlIjoiMTc2ODIzMDIwNDkiLCJ0eXAiOiJKV1QiLCJleHAiOjE1Njg1Mjc3MDgsImNvcnBDb2RlIjoiQ1JHVCIsImFsZyI6IkhTMjU2IiwiaWF0IjoxNTY3NjYzNzA4LCJsb2dpblNvdXJjZSI6IjEifQ.tE_59BIsNqGdbUe5HslFZ93_vyNQE2EUHwvlyOkCQhc", "2019-09-05")
CREATE TABLE test.user2 (`ROWKEY2` String, `AV` String, `IMEI` String, `MAC` String, `CHID` String, `PB` String, `PLAT` String, `UID` String, `PTIME` Date) ENGINE = MergeTree(PTIME, ROWKEY2, 8192)
insert into user2( ROWKEY2, AV, IMEI, MAC, CHID, PB, PLAT,UID,PTIME) values
("20190905", "2.1.6", "54b6aeba8581413ca487eda6caa62a55", "7c:76:68:19:34:16", "ttt", "HONOR", "2", "tt", "2019-09-05");
alter table user_label_uid_hive delete where id = 1000000010002
alter table user_label_uid_hive delete where user_id = 10035
select id,user_id from user_label_uid_hive where user_id = 10035
alter table user_label_uid_hive update browse_category_id = 11 where mobile_number in (13482154101) ;
alter table carendpoint_porlog_cls update utime = 999 where t_mac='VIVO-Y55A';
select count(*) from carendpoint_porlog_cls where t_mac='VIVO-Y55A' limit 10;
select * from carendpoint_porlog where t_mac='VIVO-Y55A' limit 10;
alter table carendpoint_porlog update user_agent = '999' where t_mac='VIVO-Y55A' ;
alter table carendpoint_porlog update user_agent = '666' where utime=-7200 and t_type='MI8-xiaomishouji';
OPTIMIZE table carendpoint_porlog;
select * from carendpoint_porlog where utime=-7200 and t_type='MI8-xiaomishouji'
更新时加上索引优化。这样查询才快点，十亿级别更新，十秒完成。
alter table carendpoint_porlog update user_agent = '999000' where t_mac='VIVO-Y55A' ;
alter table carendpoint_porlog delete where t_mac='VIVO-Y55A' ;
alter table carendpoint_porlog delete where utime=-7200 ;
select * from carendpoint_porlog where t_mac='VIVO-Y55A' limit 10;
select count(*) from carendpoint_porlog where t_mac='VIVO-Y55A' limit 10;
alter table user_label_uid_hive update browse_category_id = 19999 where browse_category_id in (18880);
select count(*) from user_label_uid_hive where browse_category_id in (19999);
alter table user_label_uid_hive update browse_category_id = 11888 where browse_category_id in (11);
select count(*) from user_label_uid_hive where browse_category_id in (11888);
alter table user_label_uid_hive delete where mobile_number in (13028815355) ;
--- 直接所有表数据删除
truncate table lmmbase.user_label_uid on cluster crm_4shards_1replicas;
create database test on cluster crm_4shards_1replicas;
truncate table default.t22_cluster on cluster 'crm_4shards_1replicas';
alter table cdm_dws.dws_log_full_di delete where gbizdate = '20190930' on cluster crm_4shards_1replicas;
alter table cdm_dws.dws_log_full_di on cluster crm_4shards_1replicas delete where gbizdate = '20190930' ;
drop table cdm_dwd.dwd_ord_carsh_base_df_cls on cluster crm_4shards_1replicas;
rename table cdm_dwd.dwd_ord_carsh_base_df_cls on cluster crm_4shards_1replicas;
create TABLE default.t3 ( id Int32,create_date Date ,c2 String,c3 Nullable(String) )
engine=MergeTree(create_date,id,8192);
create TABLE default.t31 ON CLUSTER crm_4shards_1replicas( id Int32,create_date Date ,c2 String,c3 Nullable(String) )
engine=MergeTree(create_date,id,8192);
create TABLE default.t3 on cluster crm_4shards_1replicas ( id Int32,create_date Date ,c2 Nullable(String) )
engine=MergeTree(create_date,id,(c3,c2),8192);
create table default.t3 on cluster crm_4shards_1replicas (id UInt8, name String, t Date)
engine = MergeTree(t, id, id, 2);
create table default.t3_cluster on cluster crm_4shards_1replicas (id UInt8, name String, t Date)
engine = Distributed('crm_4shards_1replicas', 'default', 't3', rand());
--------------------cxw --直接建表
drop DATABASE db2 ON CLUSTER crm_4shards_1replicas;
truncate table default.t1 on cluster crm_4shards_1replicas;
truncate table lmmbase.test_user2 on cluster crm_4shards_1replicas;
truncate table lmmbase.user_label_uid_hive on cluster crm_4shards_1replicas;
create TABLE default.porlog_test on cluster crm_4shards_1replicas ( mac String ,train_id Nullable(String),create_date Date) engine=MergeTree(create_date,mac,8192);
create table default.porlog_test_cls on cluster crm_4shards_1replicas ( mac String ,train_id Nullable(String),create_date Date )
engine = Distributed('crm_4shards_1replicas', 'default', 'porlog_test', rand());
create TABLE test.test2( id Int32,create_date Date ,c2 Nullable(String) )
engine=MergeTree(create_date,id,8192);
insert into default.test_cluster values
(11,'2018-10-10','11'),
(22,'2018-10-11','22'),
(33,'2018-10-11','33');
select id,create_date,c2,any(c3) from default.test_cluster;
select id,create_date,c2 from default.test_cluster where id<5
union all
select id,create_date,c2 from default.test_cluster where id>11
drop table crm_pub.prod_startdistrict_detail_cluster on cluster crm_4shards_1replicas;
drop table test.user_point_info2_cls on cluster crm_4shards_1replicas;
drop table crm_pub.biz_category_cluster on cluster crm_4shards_1replicas;
drop table lmmbase.user_label_uid_hive on cluster crm_4shards_1replicas;
drop database crm_user on cluster crm_4shards_1replicas;
drop database crm_market on cluster crm_4shards_1replicas;
create database cdm_dws on cluster crm_4shards_1replicas;
drop database test on cluster crm_4shards_1replicas;
drop table lmmbase.user_label_uid_hive on cluster crm_4shards_1replicas;
drop table lmmbase.user_label_uid_hive_cluster on cluster crm_4shards_1replicas;
clickhouse-client -m
---------------------------------output--------------------
select * from test.test_user2 INTO OUTFILE '/tmp/test_user2' format CSV;
select * from test.user_point_info limit 500000 INTO OUTFILE '/tmp/user_point_info' format CSV;
-- 复杂表查询
drop TABLE l.user_orders;
create TABLE test.user_orders( order_id Int64,create_time Date,user_id Nullable(String),
user_name Nullable(String),order_status Nullable(String),user_status Nullable(String) )
engine=MergeTree(create_time,order_id,8192);
insert into test.user_orders
select distinct order_id,create_time,user_id,user_name,order_status,user_status
from(
select order_id, user_no AS user_id,order_status,toDate(create_time) as create_time
from test.unity_order )
ANY LEFT JOIN
(select user_id,user_name,user_status,
mobile_number from default.user_user )
USING user_id ;
-------------------------select 相关格式代码-------------------------
--- union all
select id,create_date,c2 from test.test where id<5
union all
select id,create_date,c2 from test.test where id>11;
select groupArray(variable_id) from test.seo_test limit 10;
-- TSKV
SELECT Carrier, avg(DepDelay > 10) * 1000 AS c3 FROM ontime
WHERE Year = 2007 GROUP BY Carrier ORDER BY Carrier FORMAT TSKV;
--csv 逗号分割
SELECT Carrier, avg(DepDelay > 10) * 1000 AS c3 FROM ontime
WHERE Year = 2007 GROUP BY Carrier ORDER BY Carrier FORMAT CSV;
--JSON 逗号分割,可用于 http接口调用
SELECT Carrier, avg(DepDelay > 10) * 1000 AS c3 FROM ontime
WHERE Year = 2007 GROUP BY Carrier ORDER BY Carrier FORMAT JSON;
--XML 逗号分割,可用于 http接口调用
SELECT Carrier, avg(DepDelay > 10) * 1000 AS c3 FROM ontime
WHERE Year = 2007 GROUP BY Carrier ORDER BY Carrier FORMAT XML;
---生成的数据打包成json 数据格式
select user_id,groupArray(order_id) from test.unity_order GROUP BY user_id limit 10;
wget -O- -q 'http://localhost:8123/?query=SELECT 1'
----- http 请求查询结果
echo 'SELECT Carrier, avg(DepDelay > 10) * 1000 AS c3 FROM test.ontime WHERE Year = 2007 GROUP BY Carrier ORDER BY Carrier' | curl 'http://localhost:8123/?query=' --data-binary @-
格式化返回结果
echo 'SELECT Carrier, avg(DepDelay > 10) * 1000 AS c3 FROM test.ontime WHERE Year = 2007 GROUP BY Carrier ORDER BY Carrier FORMAT Pretty' | curl 'http://localhost:8123/?query=' --data-binary @-
echo 'CREATE TABLE t1 (a UInt8) ENGINE = Memory' | POST 'http://localhost:8123/'
echo 'insert into t1 (a) values (10)' | POST 'http://localhost:8123/'
GET "http://localhost:8123?query=select * from t"
echo 'drop table t1' | POST 'http://localhost:8123/'
jdbc 方式连接
https://github.com/yandex/clickhouse-jdbc
-----web访问界面
https://github.com/tabixio/tabix
clickhouse作为目前所有开源MPP计算框架中计算速度最快的，它在做多列的表，同时行数很多的表的查询时，性能是很让人兴奋的，但是在做表的join时，它的性能是不如单宽表查询的，但是了解了clickhouse在做join的时候的处理过程，利用的好的话，也会带来很大的效率提升，下面就详细介绍一下：
1.clickhouse做LEFT JOIN时的操作过程
比如做两表JOIN时，会优先计算右表结果，将右表结果存储到内存中，然后跟左边表的数据进行做match
2.join操作的秒级产出
首先，clickhouse在做单表查询时速度是快的惊人的，因此只要左表和右表查出来的数据量是不大的，那么整个查询响应时间仍然会是秒级产出的。
-- ANY LEFT JOIN -- 匹配一条则结束
select distinct order_id,user_id,user_name,user_status,
mobile_number as mobile,order_status
from(
select order_id, user_no AS user_id,order_status
from test.unity_order where order_id in(55719970 ,55720002)
) ANY LEFT JOIN
(select user_id,user_name,user_status,
mobile_number from default.user_user )
USING user_id FORMAT CSV;
-- ALL LEFT JOIN
select distinct order_id,user_id,user_name,user_status,
mobile_number as mobile,order_status
from(
select order_id, user_no AS user_id,order_status
from test.unity_order where order_id in(55719970 ,55720002)
) ALL LEFT JOIN
(select user_id,user_name,user_status,
mobile_number from default.user_user )
USING user_id FORMAT CSV;
-- 三个表相连
select distinct order_id,user_id,user_name,user_status,
mobile_number as mobile,order_status,send_time,send_id
from (
select distinct order_id,user_id,user_name,user_status,
mobile_number,order_status
from(
select order_id, user_no AS user_id,order_status
from test.unity_order_cluster where order_id in(55719970 ,55720002)
) ANY INNER JOIN
(select user_id,user_name,user_status,
mobile_number from default.user_user )
using user_id
)
ANY left JOIN
(select target as mobile_number,send_time,id as send_id
from test.mkt_sms_log_cluster )
USING mobile_number
FORMAT CSV;
---------------array join
-- https://clickhouse.yandex/docs/en/query_language/select/
--------------- array join
CREATE TABLE arrays_test (s String, arr Array(UInt8)) ENGINE = Memory;
INSERT INTO arrays_test VALUES ('Hello', [1,2]), ('World', [3,4,5]), ('Goodbye', []);
INSERT INTO arrays_test VALUES ('Goodbye2', [23]);
SELECT * FROM arrays_test;
SELECT s, arr FROM arrays_test ARRAY JOIN arr;
SELECT s, arr, a FROM arrays_test ARRAY JOIN arr AS a;
-- 针对map进行相加操作
-- 相同大小的多个数组可以在数组连接子句中进行逗号分隔。在这种情况下，连接是同时执行的
SELECT s, arr, a, num, mapped
FROM arrays_test ARRAY JOIN arr AS a, arrayEnumerate(arr) AS num, arrayMap(x -> x + 2, arr) AS mapped;
SELECT s, arr, a, num, arrayEnumerate(arr)
FROM arrays_test ARRAY JOIN arr AS a, arrayEnumerate(arr) AS num
---------------nested join
CREATE TABLE nested_test (s String, nesta Nested(x UInt8, y UInt32)) ENGINE = Memory;
INSERT INTO nested_test VALUES ('Hello', [1,2], [10,20]),
('World', [3,4,5], [30,40,50]), ('Goodbye', [], []);
INSERT INTO nested_test VALUES ('Goodbye_nest', [3,3], [101,201]);
SELECT * FROM nested_test;
SELECT s, nesta.x, nesta.y FROM nested_test ARRAY JOIN nesta;
针对某个进行查询
SELECT s, nesta.x, nesta.y FROM nested_test ARRAY JOIN nesta where nesta.x=3;
--一个用户下挂了多个订单
SELECT s, nesta.x, nesta.y FROM nested_test ARRAY JOIN nesta where s='Hello';
--对x值进行拆分
SELECT s, nesta.x, nesta.y FROM nested_test ARRAY JOIN nesta.x;
--对x值进行拆分
SELECT s, nesta.x, nesta.y FROM nested_test ARRAY JOIN nesta.y;
-- 对x，y进行拆分
SELECT s, nesta.x, nesta.y FROM nested_test ARRAY JOIN nesta.x, nesta.y;
---- 对数组进行枚举
SELECT s, num FROM nested_test ARRAY JOIN arrayEnumerate(nesta.x) as num;
--
SELECT s, n.x, n.y, nesta.x, nesta.y, num FROM nested_test
ARRAY JOIN nesta AS n, arrayEnumerate(nesta.x) as num;
------------------------nested join 2级嵌套 ----------------------------------
---
CREATE TABLE nested_test2 (s String, nest1 Nested(x UInt8, y UInt32),nest2 Nested(x2 Int64,y2 Int64))
ENGINE = Memory;
INSERT INTO nested_test2 VALUES ('Hello',[1,2],[10,20],[11,21],[11,21]),
('World', [3,4,5], [30,40,50],[31,41,51], [301,401,501]), ('Goodbye', [], [], [], []),('Goodbye_nest', [3,3], [101,201],[31,31], [1011,2011]);
INSERT INTO nested_test2 VALUES ('Goodbye_nest', [3,3], [101,201],[31,31], [1011,2011]);
SELECT * FROM nested_test2;
SELECT s, nest1.x, nest1.y,nest2.x2 FROM nested_test2 ARRAY JOIN nest1;
针对某个进行查询
SELECT s, nest1.x, nest1.y FROM nested_test2 ARRAY JOIN nest1 where nest1.x=3;
--一个用户下挂了多个订单
SELECT s, nest1.x, nest1.y,nest2.x2 ,nest2.y2 FROM nested_test2 ARRAY JOIN nest1 where s='Hello';
--对x值进行拆分
SELECT s, nest1.x, nest1.y FROM nested_test2 ARRAY JOIN nest1.x;
--对x值进行拆分
SELECT s, nest1.x, nest1.y FROM nested_test2 ARRAY JOIN nest1.y;
-- 对x，y进行拆分
SELECT s, nest1.x, nest1.y FROM nested_test2 ARRAY JOIN nest1.x, nest1.y;
---- 对数组进行枚举
SELECT s, num FROM nested_test2 ARRAY JOIN arrayEnumerate(nest1.x) as num;
--
SELECT s, n.x, n.y, nest1.x, nest1.y,num FROM nested_test2
ARRAY JOIN nest1 AS n, arrayEnumerate(nest1.x) as num;
select order_id,user_id,user_no from unity_order where user_no is null limit 10;
-- 临时表(TEMPORARY)
在所有情况下，如果指定临时表，就会创建临时表。临时表有以下特点：
临时表在会话结束时消失，包括连接丢失。
一个临时表是用内存引擎创建的。其他表引擎不受支持。
DB不能为临时表指定。它是在数据库之外创建的。
如果临时表与另一个表的名称相同，并且查询指定表名而不指定DB，则使用临时表。
对于分布式查询处理，查询中使用的临时表被传递给远程服务器。
CREATE TEMPORARY TABLE IF NOT EXISTS test.member_new_cp ENGINE = MergeTree
AS SELECT * from test.member_new;
--success
CREATE TEMPORARY TABLE IF NOT EXISTS test.member_new_cp ENGINE = Memory
AS SELECT * from test.member_new;
-- 创建视图
CREATE VIEW member_new_view AS SELECT * from test.member_new;
CREATE VIEW member_new_view_simple AS SELECT ID,user_id,member_grade from test.member_new;
drop table member_new_orders_view;
CREATE VIEW member_new_orders_view AS
SELECT user_id,count(order_id) as cnt
from (
SELECT user_id,member_grade from test.member_new
)any left join
(select user_no as user_id,order_id from test.unity_order
)using user_id
group by user_id
order by cnt desc;
drop table member_new_orders_view;
CREATE VIEW member_new_orders_view AS
SELECT user_id,count(order_id) as cnt
from (
SELECT user_id,member_grade from test.member_new
)any left join
(select user_no as user_id,order_id from test.unity_order
)using user_id
group by user_id
order by cnt desc;
-- 全匹配数据 all left join
drop table member_new_orders_view_all;
CREATE VIEW member_new_orders_view_all AS
SELECT user_id,count(order_id) as cnt
from (
SELECT user_id,member_grade from test.member_new
)all left join
(select user_no as user_id,order_id from test.unity_order
)using user_id
group by user_id
order by cnt desc;
--查询操作符和子查询可以发生在查询的任何部分，包括聚合函数和lambda函数
select id,create_date,c2,(select max(AirlineID) from test.ontime_wpp) as aa from test.test;
SELECT
EventDate,
avg(UserID IN
(
SELECT UserID
FROM test.hits
WHERE EventDate = toDate('2014-03-17')
)) AS ratio
FROM test.hits
GROUP BY EventDate
ORDER BY EventDate Asc
select length(remark) from test.unity_order limit 10;
select order_id,length(remark) len,remark ,str(remark,0,3)
from test.unity_order where length(remark) >= 1 limit 100;
--
create table t1 (id UInt16, name String) ENGINE=TinyLog;
create table t2 (id UInt16, name String) ENGINE=TinyLog;
create table t3 (id UInt16, name String) ENGINE=TinyLog;
insert into t1(id, name) values (1, 'first');
insert into t1(id, name) values (12, 'first2');
insert into t1(id, name) values (13, 'first4');
insert into t2(id, name) values (2, 'xxxx');
insert into t3(id, name) values (12, 'i am in t3');
insert into t1(id, name) values (1, 'first');
insert into test_df select 11, 'first2','2019-10-13';
CREATE TABLE default.test_df (`code` String, `description` Nullable(String), `ckbizdate` Date) ENGINE = MergeTree(ckbizdate, code, 8192);
insert into test_df select 132, 'first2','2019-10-20';
ssh dn2 'clickhouse-client --query="alter table default.test_df delete where ckbizdate =2019-10-20 " '
--表进行合并查询，不支持更新操作
create table t_merge (id UInt16, name String) ENGINE=Merge(currentDatabase(), '^t');
select * from t_merge
select _table,* from t_merge order by id desc
---
create table t_repalce (gmt Date, id UInt16, name String, point UInt16)
ENGINE=ReplacingMergeTree(gmt, (name), 10, point);
insert into t_repalce (gmt, id, name, point) values ('2017-07-10', 1, 'a', 20);
insert into t_repalce (gmt, id, name, point) values ('2017-07-10', 1, 'a', 30);
insert into t_repalce (gmt, id, name, point) values ('2017-07-11', 1, 'a', 20);
insert into t_repalce (gmt, id, name, point) values ('2017-07-11', 1, 'a', 30);
insert into t_repalce (gmt, id, name, point) values ('2017-07-11', 1, 'a', 10);
insert into t_repalce (gmt, id, name, point) values ('2017-07-11', 2, 'a', 10);
insert into t_repalce (gmt, id, name, point) values ('2017-07-11', 3, 'b', 10);
insert into t_repalce (gmt, id, name, point) values ('2017-07-11', 3, 'c', 10);
insert into t_repalce (gmt, id, name, point) values ('2017-07-11', 3, 'c', 20);
-- 多值判断
SELECT
number,
caseWithoutExpression((number > 5) AND (number < 10), number + 1,
(number >= 10) AND (number < 15), number * 2, 0)
FROM system.numbers
WHERE number < 20
LIMIT 16;
-- 行转列
select user_id,groupUniqArray(order_id)
from unity_order
group by user_id
having count(*) >4 limit 10;
select user_id,arrayMap(x-> toString(x), groupArray(order_id))
from unity_order where order_id>0 and user_id != '' group by user_id having count(*) > 4 limit 10;
-- json 格式化返回结果
select user_id,concat('[',toString(groupUniqArray(order_id)),']' ) json
from unity_order
where user_id != ''
group by user_id
having count(*) >4 limit 10;
参考技术
https://www.zouyesheng.com/clickhouse.html#toc8
https://blog.csdn.net/vagabond6/article/details/79556968
https://zhuanlan.zhihu.com/p/22165241
常用函数
https://blog.csdn.net/vagabond6/article/details/79580371
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版权声明：本文为CSDN博主「wppwpp1」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/wppwpp1/java/article/details/106021361