You can't store tuples in tables (other than Memory tables). They are used for temporary column grouping. Columns can be grouped when an IN expression is used in a query, and for specifying certain formal parameters of lambda functions. For more information, see the sections [IN operators](../query_language/select.md) and [Higher order functions](../query_language/functions/higher_order_functions.md).
Tuples can be the result of a query. In this case, for text formats other than JSON, values are comma-separated in brackets. In JSON formats, tuples are output as arrays (in square brackets).
When creating a tuple on the fly, ClickHouse automatically detects the type of each argument as the minimum of the types which can store the argument value. If the argument is [NULL](../query_language/syntax.md#null-literal), the type of the tuple element is [Nullable](nullable.md).