--- navigation_title: Query multiple indices mapped_pages: - https://www.elastic.co/guide/en/elasticsearch/reference/current/esql-multi-index.html applies_to: stack: ga serverless: ga products: - id: elasticsearch --- # Use ES|QL to query multiple indices [esql-multi-index] With {{esql}}, you can execute a single query across multiple indices, data streams, or aliases. To do so, use wildcards and date arithmetic. The following example uses a comma-separated list and a wildcard: ```esql FROM employees-00001,other-employees-* ``` Use the format `:` to [query data streams and indices on remote clusters](esql-cross-clusters.md): ```esql FROM cluster_one:employees-00001,cluster_two:other-employees-* ``` ## Field type mismatches [esql-multi-index-invalid-mapping] When querying multiple indices, data streams, or aliases, you might find that the same field is mapped to multiple different types. For example, consider the two indices with the following field mappings: **index: events_ip** ``` { "mappings": { "properties": { "@timestamp": { "type": "date" }, "client_ip": { "type": "ip" }, "event_duration": { "type": "long" }, "message": { "type": "keyword" } } } } ``` **index: events_keyword** ``` { "mappings": { "properties": { "@timestamp": { "type": "date" }, "client_ip": { "type": "keyword" }, "event_duration": { "type": "long" }, "message": { "type": "keyword" } } } } ``` When you query each of these individually with a simple query like `FROM events_ip`, the results are provided with type-specific columns: ```esql FROM events_ip | SORT @timestamp DESC ``` | @timestamp:date | client_ip:ip | event_duration:long | message:keyword | | --- | --- | --- | --- | | 2023-10-23T13:55:01.543Z | 172.21.3.15 | 1756467 | Connected to 10.1.0.1 | | 2023-10-23T13:53:55.832Z | 172.21.3.15 | 5033755 | Connection error | | 2023-10-23T13:52:55.015Z | 172.21.3.15 | 8268153 | Connection error | Note how the `client_ip` column is correctly identified as type `ip`, and all values are displayed. However, if instead the query sources two conflicting indices with `FROM events_*`, the type of the `client_ip` column cannot be determined and is reported as `unsupported` with all values returned as `null`. $$$query-unsupported$$$ ```esql FROM events_* | SORT @timestamp DESC ``` | @timestamp:date | client_ip:unsupported | event_duration:long | message:keyword | | --- | --- | --- | --- | | 2023-10-23T13:55:01.543Z | null | 1756467 | Connected to 10.1.0.1 | | 2023-10-23T13:53:55.832Z | null | 5033755 | Connection error | | 2023-10-23T13:52:55.015Z | null | 8268153 | Connection error | | 2023-10-23T13:51:54.732Z | null | 725448 | Connection error | | 2023-10-23T13:33:34.937Z | null | 1232382 | Disconnected | | 2023-10-23T12:27:28.948Z | null | 2764889 | Connected to 10.1.0.2 | | 2023-10-23T12:15:03.360Z | null | 3450233 | Connected to 10.1.0.3 | In addition, if the query refers to this unsupported field directly, the query fails: ```esql FROM events_* | SORT client_ip DESC ``` ```bash Cannot use field [client_ip] due to ambiguities being mapped as [2] incompatible types: [ip] in [events_ip], [keyword] in [events_keyword] ``` ## Union types [esql-multi-index-union-types] ::::{warning} This functionality is in technical preview and may be changed or removed in a future release. Elastic will work to fix any issues, but features in technical preview are not subject to the support SLA of official GA features. :::: {{esql}} has a way to handle [field type mismatches](#esql-multi-index-invalid-mapping). When the same field is mapped to multiple types in multiple indices, the type of the field is understood to be a *union* of the various types in the index mappings. As seen in the preceding examples, this *union type* cannot be used in the results, and cannot be referred to by the query — except in `KEEP`, `DROP` or when it’s passed to a type conversion function that accepts all the types in the *union* and converts the field to a single type. {{esql}} offers a suite of [type conversion functions](functions-operators/type-conversion-functions.md) to achieve this. In the above examples, the query can use a command like `EVAL client_ip = TO_IP(client_ip)` to resolve the union of `ip` and `keyword` to just `ip`. You can also use the type-conversion syntax `EVAL client_ip = client_ip::IP`. Alternatively, the query could use [`TO_STRING`](functions-operators/type-conversion-functions.md#esql-to_string) to convert all supported types into `KEYWORD`. For example, the [query](#query-unsupported) that returned `client_ip:unsupported` with `null` values can be improved using the `TO_IP` function or the equivalent `field::ip` syntax. These changes also resolve the error message. As long as the only reference to the original field is to pass it to a conversion function that resolves the type ambiguity, no error results. ```esql FROM events_* | EVAL client_ip = TO_IP(client_ip) | KEEP @timestamp, client_ip, event_duration, message | SORT @timestamp DESC ``` | @timestamp:date | client_ip:ip | event_duration:long | message:keyword | | --- | --- | --- | --- | | 2023-10-23T13:55:01.543Z | 172.21.3.15 | 1756467 | Connected to 10.1.0.1 | | 2023-10-23T13:53:55.832Z | 172.21.3.15 | 5033755 | Connection error | | 2023-10-23T13:52:55.015Z | 172.21.3.15 | 8268153 | Connection error | | 2023-10-23T13:51:54.732Z | 172.21.3.15 | 725448 | Connection error | | 2023-10-23T13:33:34.937Z | 172.21.0.5 | 1232382 | Disconnected | | 2023-10-23T12:27:28.948Z | 172.21.2.113 | 2764889 | Connected to 10.1.0.2 | | 2023-10-23T12:15:03.360Z | 172.21.2.162 | 3450233 | Connected to 10.1.0.3 | ## Index metadata [esql-multi-index-index-metadata] It can be helpful to know the particular index from which each row is sourced. To get this information, use the [`METADATA`](esql-metadata-fields.md) option on the [`FROM`](commands/from.md) command. ```esql FROM events_* METADATA _index | EVAL client_ip = TO_IP(client_ip) | KEEP _index, @timestamp, client_ip, event_duration, message | SORT @timestamp DESC ``` | _index:keyword | @timestamp:date | client_ip:ip | event_duration:long | message:keyword | | --- | --- | --- | --- | --- | | events_ip | 2023-10-23T13:55:01.543Z | 172.21.3.15 | 1756467 | Connected to 10.1.0.1 | | events_ip | 2023-10-23T13:53:55.832Z | 172.21.3.15 | 5033755 | Connection error | | events_ip | 2023-10-23T13:52:55.015Z | 172.21.3.15 | 8268153 | Connection error | | events_keyword | 2023-10-23T13:51:54.732Z | 172.21.3.15 | 725448 | Connection error | | events_keyword | 2023-10-23T13:33:34.937Z | 172.21.0.5 | 1232382 | Disconnected | | events_keyword | 2023-10-23T12:27:28.948Z | 172.21.2.113 | 2764889 | Connected to 10.1.0.2 | | events_keyword | 2023-10-23T12:15:03.360Z | 172.21.2.162 | 3450233 | Connected to 10.1.0.3 |