# INSERT INTO

## Syntax <a href="#synopsis" id="synopsis"></a>

```sql
INSERT INTO
    relation_name
    select_statement;
```

## Description <a href="#description" id="description"></a>

For an existing Relation, `INSERT INTO` runs the given query (i.e. a `SELECT` statement) and adds its results into the sink Relation. The list of columns of the sink Relation and the `SELECT` columns list in the query should be data type compatible. Moreover, the Relation type of a sink Relation should match with the Relation type of query results. For example, the results of a query that uses grouping aggregation cannot be inserted into a [Database](/overview/core-concepts/databases.md#_stream) as the result type for a query with `GROUP BY` as a [Database](/overview/core-concepts/databases.md#_changelog).

{% hint style="info" %}
`INSERT INTO` does not support `MATERIALIZED VIEW` as the sink Relation.
{% endhint %}

### Arguments <a href="#parameters" id="parameters"></a>

#### relation\_name

This specifies the name of the Relation to add results to. Relation names can be specified as fully/partially qualified names via the specifying database\_name and/or schema\_name in the format `[<database_name>.<schema_name>.]<relation_name>` (such as `db1.public.pageviews`). Otherwise, the current Database and Schema will be used to identify the Relation. For case-sensitive names, the name must be wrapped in double quotes; otherwise, the lowercase name will be used.

#### select\_statement

This clause specifies the `SELECT` statement to run; see [SELECT](/reference/sql-syntax/query/select.md) for more information.

## Examples

#### Select all `INSERT INTO`

The following copies all data from the source Relation and inserts it into a preexisting Relation.

```sql
INSERT INTO pageviews2 SELECT * FROM pageviews;
```

#### `INSERT INTO` with grouping and aggregation

The following runs a query that finds the average `ViewTime` in a 5 second window and inserts the results into the already existing Relation `Aggr Pageviews2`.

```sql
INSERT INTO
  "Aggr Pageviews2" 
SELECT 
  window_start, 
  window_end, 
  avg("ViewTime") AS "AvgTime", 
  "UserID", 
  "pageId" 
FROM TUMBLE("CaseSensitivePageviews", size 5 second) 
GROUP BY 
  window_start, 
  window_end, 
  "UserID", 
  "pageId";
```

#### Combine multiple queries’ results with `INSERT INTO`

`INSERT INTO` can be used to combine the results of multiple queries into a single sink Relation, as long as:

* Every query has the same sink Relation type.
* The `SELECT` columns list in every query has the same number of columns, with similar data types, in the same order.

For example, assume two Changelogs are created from the `users` Stream to collect stats on the total number of users in different cities in Europe and the U.S.

```sql
CREATE CHANGELOG users_eu
AS SELECT contactinfo->city AS city, count(userid) AS ucount
FROM users
WHERE regionid = 'EUROPE'
GROUP BY contactinfo->city;

CREATE CHANGELOG users_us
AS SELECT contactinfo->city AS city, count(userid) AS ucount
FROM users
WHERE regionid = 'US'
GROUP BY contactinfo->city;
```

Moreover, assume we are interested in keeping track of cities in Europe or the U.S. with more than a thousand users, in a single Relation. We can create a third Changelog, named `total_users`, with the below DDL and use the following two `INSERT INTO` statements to combine results from the above Changelogs and add them to the `total_users` Changelog:

```sql
CREATE CHANGELOG total_users (
   city VARCHAR,
   total_cnt BIGINT,
   PRIMARY KEY(city)
)
WITH (
   'topic'='total_users',
   'value.format'='json'
);
```

```sql
INSERT INTO total_users
SELECT * FROM users_eu
WHERE ucount > 1000;
```

```sql
INSERT INTO total_users
SELECT * FROM users_us
WHERE ucount > 1000;
```


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