ClickHouse/docs/en/query_language/functions/ext_dict_functions.md

Functions for working with external dictionaries

For information on connecting and configuring external dictionaries, see "External dictionaries".

dictGetUInt8, dictGetUInt16, dictGetUInt32, dictGetUInt64

dictGetInt8, dictGetInt16, dictGetInt32, dictGetInt64

dictGetFloat32, dictGetFloat64

dictGetDate, dictGetDateTime

dictGetUUID

dictGetString

dictGetT('dict_name', 'attr_name', id)

• Get the value of the attr_name attribute from the dict_name dictionary using the 'id' key.dict_name and attr_name are constant strings.idmust be UInt64. If there is no id key in the dictionary, it returns the default value specified in the dictionary description.

dictGetTOrDefault

dictGetT('dict_name', 'attr_name', id, default)

The same as the dictGetT functions, but the default value is taken from the function's last argument.

dictIsIn

dictIsIn ('dict_name', child_id, ancestor_id)

• For the 'dict_name' hierarchical dictionary, finds out whether the 'child_id' key is located inside 'ancestor_id' (or matches 'ancestor_id'). Returns UInt8.

dictGetHierarchy

dictGetHierarchy('dict_name', id)

• For the 'dict_name' hierarchical dictionary, returns an array of dictionary keys starting from 'id' and continuing along the chain of parent elements. Returns Array(UInt64).

dictHas

dictHas('dict_name', id)

• Check whether the dictionary has the key. Returns a UInt8 value equal to 0 if there is no key and 1 if there is a key.