JSONAsObject

描述

在此格式中，单个 JSON 对象被解释为单个 JSON 值。如果输入包含多个 JSON 对象（以逗号分隔），则将其解释为单独的行。如果输入数据用方括号括起来，则会被解释为 JSON 数组。

此格式仅能用于具有单个 JSON 类型字段的表。其余列必须设置为 DEFAULT 或 MATERIALIZED。

示例用法

基本示例

CREATE TABLE json_as_object (json JSON) ENGINE = Memory;
INSERT INTO json_as_object (json) FORMAT JSONAsObject {"foo":{"bar":{"x":"y"},"baz":1}},{},{"any json stucture":1}
SELECT * FROM json_as_object FORMAT JSONEachRow;

{"json":{"foo":{"bar":{"x":"y"},"baz":"1"}}}
{"json":{}}
{"json":{"any json stucture":"1"}}

JSON 对象数组

CREATE TABLE json_square_brackets (field JSON) ENGINE = Memory;
INSERT INTO json_square_brackets FORMAT JSONAsObject [{"id": 1, "name": "name1"}, {"id": 2, "name": "name2"}];
SELECT * FROM json_square_brackets FORMAT JSONEachRow;

{"field":{"id":"1","name":"name1"}}
{"field":{"id":"2","name":"name2"}}

带默认值的列

CREATE TABLE json_as_object (json JSON, time DateTime MATERIALIZED now()) ENGINE = Memory;
INSERT INTO json_as_object (json) FORMAT JSONAsObject {"foo":{"bar":{"x":"y"},"baz":1}};
INSERT INTO json_as_object (json) FORMAT JSONAsObject {};
INSERT INTO json_as_object (json) FORMAT JSONAsObject {"any json stucture":1}
SELECT time, json FROM json_as_object FORMAT JSONEachRow

{"time":"2024-09-16 12:18:10","json":{}}
{"time":"2024-09-16 12:18:13","json":{"any json stucture":"1"}}
{"time":"2024-09-16 12:18:08","json":{"foo":{"bar":{"x":"y"},"baz":"1"}}}

格式设置