Data Types in ClickHouse

View as MarkdownEdit this pageReport an issueSet up docs MCP

This section describes the data types supported by ClickHouse, for example integers, floats and strings.

Different data types can benefit from different compression codecs.

System table system.data_type_families provides an overview of all available data types. It also shows whether a data type is an alias to another data type and its name is case-sensitive (e.g. bool vs. BOOL).

Data type categories

Numeric types

Store integers, floating-point values, fixed-precision Decimal values, and Bool flags.

String types

Store variable-length String values or fixed-length FixedString values.

Date and time types

Represent dates with Date and Date32, timestamps with DateTime and DateTime64, or time values with Time and Time64.

Network types

Store IPv4 and IPv6 addresses in compact binary form.

Composite types

Combine values in Array, Tuple, Map, and Nested structures.

Semi-structured types

Store evolving or heterogeneous data with JSON, Dynamic, and Variant.

Nullable and optional types

Represent missing values with Nullable, or reduce storage for repeated values with LowCardinality.

Specialized types

Model UUID values, Enum values, geographic objects, vectors for approximate search, and domains.

Aggregate function types

Store intermediate aggregation states with AggregateFunction and SimpleAggregateFunction.

Special Data Types

Learn about Expression, Interval, Nothing, and Set, which are used for intermediate query results.

Binary encoding

See the binary encoding specification for the serialized representation of each data type.