# EXISTS condition
<a name="exists_condition"></a>

EXISTS conditions test for the existence of rows in a subquery, and return true if a subquery returns at least one row. If NOT is specified, the condition returns true if a subquery returns no rows.

## Syntax
<a name="exists_condition-synopsis"></a>

```
[ NOT ] EXISTS (table_subquery)
```

## Arguments
<a name="exists_condition-arguments"></a>

 EXISTS   
Is true when the *table\$1subquery* returns at least one row.

NOT EXISTS   
Is true when the *table\$1subquery* returns no rows.

 *table\$1subquery*   
A subquery that evaluates to a table with one or more columns and one or more rows.

## Example
<a name="exists_condition-example"></a>

This example returns all date identifiers, one time each, for each date that had a sale of any kind:

```
select dateid from date
where exists (
select 1 from sales
where date.dateid = sales.dateid
)
order by dateid;

dateid
--------
1827
1828
1829
...
```