ch_union_query

Wraps each input sub-query as a derived table and combines them with
<code>UNION DISTINCT</code> or <code>UNION ALL</code>. A single sub-query is returned wrapped but
without any <code>UNION</code> clause.

Facilitate the management of data from knowledge
resources that are frequently used alone or together
in research environments.
In 'TKCat', knowledge resources are manipulated as modeled database (MDB)
objects. These objects provide access to the data tables along with a general
description of the resource and a detailed data model documenting the
tables, their fields and their relationships.
These MDBs are then gathered in catalogs that can be easily
explored and shared.
Finally, 'TKCat' provides tools to easily subset, filter and combine MDBs and
create new catalogs suited for specific needs.

Patrice Godard

TKCat

Tailored Knowledge Catalog

ch_union_query function

<dl><dt>queries</dt>
<dd>a character vector of <code>SELECT</code> sub-queries to combine</dd>
<dt>mode</dt>
<dd>the union mode: <code>"DISTINCT"</code> (default) to deduplicate rows
across sub-queries, or <code>"ALL"</code> to keep every row</dd></dl>

Arguments

Build a ClickHouse UNION query from several sub-queries — ch_union_query

<dl>

<dt>queries</dt>
<dd>a character vector of <code>SELECT</code> sub-queries to combine</dd>


<dt>mode</dt>
<dd>the union mode: <code>"DISTINCT"</code> (default) to deduplicate rows
across sub-queries, or <code>"ALL"</code> to keep every row</dd>

</dl>

ch_union_query: Build a ClickHouse `UNION` query from several sub-queries

Description

Usage

Value

Arguments

See Also