In this post, we will see how to resolve how to concat two columns value in clickhouse Question: I have two columns, one with date (yyyy-mm-dd) Nullable(Date) and another with hour (hh) Nullable(UInt8), and I need to write a select ...

In this post, we will see how to resolve Clickhouse-copier SAXParseException: Syntax error in line 1 column 0 Question: I need to transfer some tables with data between two servers. I tried using clickhouse-copier, but I get SAXParseException: Syntax error ...

In this post, we will see how to resolve Clickhouse not working after losing zookeeper cluster, how to force it to generate new metadata Question: I am setting up Posthog which includes Clickhouse and connects to Zookeeper. It was set ...

In this post, we will see how to resolve Selecting over a with clause that contains union all Question: Assume that you have a student table in clickhouse. The query is here: I am getting table Default.a doesnt exist (unknown ...

In this post, we will see how to resolve Is my network port available to the outside world? Question: Background First time working with Azure. I’m deploying a database server (ClickHouse) onto a VM hosted in Azure, and have it ...

Question: I need to join two datasets from e.g. left and right source to match values by some keys. Datasets can contain duplicates: I cant use full join, it gives cartesian products of all duplicates. I am trying to use ...

Question: Is there any option how to create a computed column in the CREATE TABLE statement? Something like generated column in PostgreSQL or computed column in T-SQL If there is no similar option, what could be the alternative please? My ...

Question: In clickhouse version 22.1 it is possible to inference schema. e.g.: DESC file('nonexist', 'Protobuf') SETTINGS format_schema='file.proto:LogEntry' But is it possible to create table with columns obtained from DESCRIBE? Answer: yes If you have better answer, please add a comment ...

Question: I am running multiple queries using one session. I have to create a Temporary table and then I have to insert data from CSV to that file and after that, I have to insert data into a Permanent table. ...

Question: I have multiple similar SQL queries that I need to run in Go code. Something like this: Is there a way to use one struct for all 3 queries? Ideally S1 being used for all 3 queries would be ...