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Multiple Matching Databases - KNIME Forum (90823)

<p>Multiple Matches with local databases H2 and DuckDB</p><p></p><p><strong>KNIME, Databases and SQL</strong></p><p>https://medium.com/p/273e27c9702a</p>

URL: Maven - DuckDB Driver .jar https://mvnrepository.com/artifact/org.duckdb/duckdb_jdbc
URL: DuckDB - toy around with KNIME and SQL https://forum.knime.com/t/when-using-duckdb-with-knime-getting-error-execute-failed-a-local-transaction-already-exists/40828/7?u=mlauber71
URL: Blog: KNIME, Databases and SQL https://medium.com/p/273e27c9702a

Multiple Matches with local databases H2 and DuckDB

https://forum.knime.com/t/method-request-for-big-data/90823/5?u=mlauber71

DuckDB - toy around with KNIME and SQL

https://forum.knime.com/t/when-using-duckdb-with-knime-getting-error-execute-failed-a-local-transaction-already-exists/40828/7?u=mlauber71

https://hub.knime.com/s/1p_14IrKMhA5QNIb

KNIME, Databases and SQL

https://medium.com/p/273e27c9702a

Create Unique ID
DB Connection Extractor
results
DB Table Creator
CASE Switch Start
sample_table1.csv
CSV Reader
Variable Loop End
table2
DB Writer
DROP TABLE IF EXISTS main.results
DB SQL Executor
CASE Switch End
DROP TABLE IF EXISTS main.table2
DB SQL Executor
active_port
Variable Expression
sample_table3.csv
CSV Reader
DB Table Creator
DB Table Selector
sample_table2.csv
CSV Reader
DB Reader
DB Table Creator
DROP TABLE IF EXISTS main.table3
DB SQL Executor
table3
DB Writer
Column Renamer
DB Table Creator
DB Writer
DB Connection Extractor
Column Renamer
Column Renamer
DROP TABLE IF EXISTS PUBLIC.table1
DB SQL Executor
Column Renamer
Create Unique ID
jdbc:duckdb::memory:A DuckDB in memory
DB Connector
SELECT * FROM information_schema.schemata
DB Query Reader
SHOW ALL TABLES;
DB Query Reader
table2.csv
CSV Reader
2match A, B
DB Joiner
H2 Connector
SELECT * FROM information_schema.schemata
DB Query Reader
SELECT * FROM #table# T1WHERE "A" = '$${SA}$$'AND "B" = '$${SB}$$'
DB Query
DROP TABLE IF EXISTS PUBLIC.table2
DB SQL Executor
Table Row to Variable Loop Start
DB Concatenate
DB Reader
Column Renamer
DB Concatenate
DB Query
1
DB Joiner
SELECT * FROM #table# T1WHERE "A" = '$${SA}$$'AND "B" = '$${SB}$$'
DB Query
2match A, B
DB Joiner
SHOW DATABASES;
DB Query Reader
table1.csv
CSV Reader
table2
DB Writer
Variable Loop End
Table Row to Variable Loop Start
1
DB Joiner
DB Table Creator
PUBLIC.results
DB Table Selector
table3.csv
CSV Reader
DROP TABLE IF EXISTS PUBLIC.table3
DB SQL Executor
table3
DB Writer
DB Query
DB Table Creator
SHOW DATABASES;
DB Query Reader
DB Connection Extractor
result_h2.table
Table Writer
SHOW DATABASES;
DB Query Reader
DB Writer
result_duckdb.table
Table Writer
Column Renamer
SELECT *FROM INFORMATION_SCHEMA.COLUMNSWHERE TABLE_SCHEMA = 'PUBLIC'
DB Query Reader
H2 does support writingVIEWs directly into tables
DB Writer (DB Data)
DB Table Creator
Create Unique ID
DROP TABLE IF EXISTS main.table1
DB SQL Executor
Create Unique ID
DB Reader
Create Unique ID
DB Writer
Create Unique ID

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To use this workflow in KNIME, download it from the below URL and open it in KNIME:

Download Workflow
Created by: m_lauber
Created at: 2024-12-28
On NodePit since: 2025-11-29
Last update: 2026-01-08
Created with KNIME version: v5.8.1
Tags: DBSQLdatabaseDuckDB

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