# Ad-hoc converter

Published articles for Ad-hoc converter.

This is one page of public article previews, not the complete archive. Follow Next page to continue. Summaries are not the original full articles.

## How to use jOOQ's Converters with UNION Operations

DevFeed: [How to use jOOQ's Converters with UNION Operations](<https://devfeed.tech/articles/how-to-use-jooq-s-converters-with-union-operations-28947.md>)

Original publisher: [Read original article](<https://blog.jooq.org/how-to-use-jooqs-converters-with-union-operations/>)

Author: lukaseder

Published: 2023-03-02T11:18:17Z

Content type: tutorial

Language: en

Sources: [jOOQ](<https://devfeed.tech/sources/jooq.md>)

Topics: [SQL](<https://devfeed.tech/topics/sql.md>), [Databases](<https://devfeed.tech/topics/databases.md>)

Tags: [ad-hoc-converter](<https://devfeed.tech/tags/ad-hoc-converter.md>), [converter](<https://devfeed.tech/tags/converter.md>), [how-to](<https://devfeed.tech/tags/how-to.md>), [jdbc](<https://devfeed.tech/tags/jdbc.md>), [jooq](<https://devfeed.tech/tags/jooq.md>), [jooq-in-use](<https://devfeed.tech/tags/jooq-in-use.md>), [lambda](<https://devfeed.tech/tags/lambda.md>), [multiset](<https://devfeed.tech/tags/multiset.md>), [r2dbc](<https://devfeed.tech/tags/r2dbc.md>), [rdbms](<https://devfeed.tech/tags/rdbms.md>), [sql](<https://devfeed.tech/tags/sql.md>), [union](<https://devfeed.tech/tags/union.md>)

### AI overview

This tutorial explains how jOOQ ad-hoc converters behave with UNION operations. Because conversion occurs on the client after JDBC retrieval, it does not affect server-side UNION processing, and jOOQ applies the result-fetching row type from the first subquery. The article recommends applying client-side conversions consistently across subqueries or moving the conversion to the server when appropriate.

### Source excerpt

jOOQ 3.15 introduced the concept of an ad-hoc converter, a converter that is applied "ad-hoc" to a single query. It uses the same underlying mechanisms as any ordinary Converter that is attached to generated code for use in every query. An example of such an ad-hoc converter is this: While there are other ways to ... Continue reading How to use jOOQ's Converters with UNION Operations ->