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* Corrected en files * Split system-tables.md into separate files * Fixed links. * Fixed links. * Fixed links. * Fixed links. * Add ref to original article * Fixed links * Add toc_folder_title and translate * Add stack_trace.md, correct toc-title * Fixed links * Hypothesis testing * Hypothesis testing * Update run.sh, thanks @azat Co-authored-by: Anna Devyatova <annadevyatova@yandex-team.ru> Co-authored-by: Sergei Shtykov <bayonet@yandex-team.ru> Co-authored-by: alexey-milovidov <milovidov@yandex-team.ru>
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system.columns
Contains information about columns in all the tables.
You can use this table to get information similar to the DESCRIBE TABLE query, but for multiple tables at once.
The system.columns table contains the following columns (the column type is shown in brackets):
database(String) — Database name.table(String) — Table name.name(String) — Column name.type(String) — Column type.default_kind(String) — Expression type (DEFAULT,MATERIALIZED,ALIAS) for the default value, or an empty string if it is not defined.default_expression(String) — Expression for the default value, or an empty string if it is not defined.data_compressed_bytes(UInt64) — The size of compressed data, in bytes.data_uncompressed_bytes(UInt64) — The size of decompressed data, in bytes.marks_bytes(UInt64) — The size of marks, in bytes.comment(String) — Comment on the column, or an empty string if it is not defined.is_in_partition_key(UInt8) — Flag that indicates whether the column is in the partition expression.is_in_sorting_key(UInt8) — Flag that indicates whether the column is in the sorting key expression.is_in_primary_key(UInt8) — Flag that indicates whether the column is in the primary key expression.is_in_sampling_key(UInt8) — Flag that indicates whether the column is in the sampling key expression.