distinctJSONPaths
Calculates the list of distinct paths stored in JSON column.
Syntax
distinctJSONPaths(json)
Arguments
json— JSON column.
Returned Value
- The sorted list of paths Array(String).
Example
Query:
DROP TABLE IF EXISTS test_json;
CREATE TABLE test_json(json JSON) ENGINE = Memory;
INSERT INTO test_json VALUES ('{"a" : 42, "b" : "Hello"}'), ('{"b" : [1, 2, 3], "c" : {"d" : {"e" : "2020-01-01"}}}'), ('{"a" : 43, "c" : {"d" : {"f" : [{"g" : 42}]}}}')
SELECT distinctJSONPaths(json) FROM test_json;
Result:
┌─distinctJSONPaths(json)───┐
│ ['a','b','c.d.e','c.d.f'] │
└───────────────────────────┘
distinctJSONPathsAndTypes
Calculates the list of distinct paths and their types stored in JSON column.
Syntax
distinctJSONPathsAndTypes(json)
Arguments
json— JSON column.
Returned Value
- The sorted map of paths and types Map(String, Array(String)).
Example
Query:
DROP TABLE IF EXISTS test_json;
CREATE TABLE test_json(json JSON) ENGINE = Memory;
INSERT INTO test_json VALUES ('{"a" : 42, "b" : "Hello"}'), ('{"b" : [1, 2, 3], "c" : {"d" : {"e" : "2020-01-01"}}}'), ('{"a" : 43, "c" : {"d" : {"f" : [{"g" : 42}]}}}')
SELECT distinctJSONPathsAndTypes(json) FROM test_json;
Result:
┌─distinctJSONPathsAndTypes(json)───────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ {'a':['Int64'],'b':['Array(Nullable(Int64))','String'],'c.d.e':['Date'],'c.d.f':['Array(JSON(max_dynamic_types=16, max_dynamic_paths=256))']} │
└───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
Note
If JSON declaration contains paths with specified types, these paths will be always included in the result of distinctJSONPaths/distinctJSONPathsAndTypes functions even if input data didn't have values for these paths.
DROP TABLE IF EXISTS test_json;
CREATE TABLE test_json(json JSON(a UInt32)) ENGINE = Memory;
INSERT INTO test_json VALUES ('{"b" : "Hello"}'), ('{"b" : "World", "c" : [1, 2, 3]}');
SELECT json FROM test_json;
┌─json──────────────────────────────────┐
│ {"a":0,"b":"Hello"} │
│ {"a":0,"b":"World","c":["1","2","3"]} │
└───────────────────────────────────────┘
SELECT distinctJSONPaths(json) FROM test_json;
┌─distinctJSONPaths(json)─┐
│ ['a','b','c'] │
└─────────────────────────┘
SELECT distinctJSONPathsAndTypes(json) FROM test_json;
┌─distinctJSONPathsAndTypes(json)────────────────────────────────┐
│ {'a':['UInt32'],'b':['String'],'c':['Array(Nullable(Int64))']} │
└────────────────────────────────────────────────────────────────┘