# Search External Tables with Confluent Cloud for Apache Flink Confluent Cloud for Apache Flink® supports read-only external tables to enable different types of search with federated query execution on external databases. #### NOTE Egress and ingress data transfers from Flink are offered at no cost until 3/31/2026. - [Key search with external databases](key-search.md#flink-sql-key-search): Perform lookups on exact key matches. - [Text search with external databases](text-search.md#flink-sql-text-search): Ideal for precise queries where exact word matches are desired. Less computationally intensive than vector search and can be used independently or in combination depending on the use case. - [Vector search with external databases](vector-search.md#flink-sql-vector-search): Use an input string to query vector space in an external vector database for semantic queries. #### IMPORTANT External calls in stream processing enable powerful use cases like real-time enrichment and AI orchestration but may introduce risks: reprocessing can overwhelm external systems with replay traffic, network failures or high latency can cascade to entire pipelines, and historical replays may get current data instead of point-in-time state, breaking audit consistency. Success requires evaluating each use case’s criticality, volume patterns, and consistency requirements to choose the right implementation pattern. Private networking is supported for external tables. For more information, see [Private Networking with Confluent Cloud for Apache Flink](../../flink/concepts/flink-private-networking.md#flink-sql-private-networking). - [Key Search with External Databases](key-search.md#flink-sql-key-search) - [Text Search with External Databases](text-search.md#flink-sql-text-search) - [Vector Search with External Databases](vector-search.md#flink-sql-vector-search) ## Related content - [External Tables](../../flink/concepts/external-tables.md#flink-external-tables) - [Lookup Joins](../../flink/reference/queries/joins.md#flink-sql-lookup-joins) - [Search Functions](../../flink/reference/functions/search-functions.md#flink-sql-search-functions) - [KEY_SEARCH_AGG function](../../flink/reference/functions/search-functions.md#flink-sql-key-search-function) - [TEXT_SEARCH_AGG function](../../flink/reference/functions/search-functions.md#flink-sql-text-search-function) - [VECTOR_SEARCH_AGG function](../../flink/reference/functions/search-functions.md#flink-sql-vector-search-function) #### NOTE This website includes content developed at the [Apache Software Foundation](https://www.apache.org/) under the terms of the [Apache License v2](https://www.apache.org/licenses/LICENSE-2.0.html).