---
title: 'Source row existence'
---

# Source row existence

Update a target column based on the existence of a source row:

import {
  Playground,
  exampleSetup,
} from '../../../src/components/Playground'

import {
  sourceRowExistence
} from './0010-source-row-existence'

<div style={{ marginBottom: '1em' }}>
  <Playground code={sourceRowExistence} setupCode={exampleSetup} />
</div>

:::info[More examples]
The API documentation is packed with examples. The API docs are hosted [here](https://kysely-org.github.io/kysely-apidoc/),
but you can access the same documentation by hovering over functions/methods/classes in your IDE. The examples are always
just one hover away!

For example, check out these sections:
 - [mergeInto method](https://kysely-org.github.io/kysely-apidoc/classes/Kysely.html#mergeInto)
 - [using method](https://kysely-org.github.io/kysely-apidoc/classes/MergeQueryBuilder.html#using)
 - [whenMatched method](https://kysely-org.github.io/kysely-apidoc/classes/WheneableMergeQueryBuilder.html#whenMatched)
 - [thenUpdateSet method](https://kysely-org.github.io/kysely-apidoc/classes/MatchedThenableMergeQueryBuilder.html#thenUpdateSet)
 - [thenDelete method](https://kysely-org.github.io/kysely-apidoc/classes/MatchedThenableMergeQueryBuilder.html#thenDelete)
 - [thenDoNothing method](https://kysely-org.github.io/kysely-apidoc/classes/MatchedThenableMergeQueryBuilder.html#thenDoNothing)
 - [whenNotMatched method](https://kysely-org.github.io/kysely-apidoc/classes/WheneableMergeQueryBuilder.html#whenNotMatched)
 - [thenInsertValues method](https://kysely-org.github.io/kysely-apidoc/classes/NotMatchedThenableMergeQueryBuilder.html#thenInsertValues)
:::
