初始化操作

创建表

CREATE TABLE orders (  "ID" int8 NOT NULL,
                       "info_j" json NOT NULL,
                       "info_t" text NOT NULL
);

初始化表

INSERT INTO orders("ID", "info_j","info_t") VALUES (1, '{"name":"张三","items":{"product":"啤酒","qty":6}}','{"name":"张三","items":{"product":"啤酒","qty":6}}');
INSERT INTO orders("ID", "info_j","info_t") VALUES (2, '{"name":"李四","items":{"product":"辣条","qty":8}}','{"name":"李四","items":{"product":"辣条","qty":8}}');
INSERT INTO orders("ID", "info_j","info_t") VALUES (3, '{"name":"王五","items":{"product":"苹果","qty":18}}','{"name":"王五","items":{"product":"苹果","qty":18}}');
INSERT INTO orders("ID", "info_j","info_t") VALUES (4, '{"name":"赵一","items":{"product":"香蕉","qty":20}}','{"name":"赵一","items":{"product":"香蕉","qty":20}}');

查询表

解析JSON字段

查询使用->操作符，查询json中所有顾客作为键

SELECT info_j -> 'name' AS customer FROM orders;

下面使用->>操作获取所有顾客姓名作为值

SELECT info_j ->> 'name' AS customer FROM orders;

根据json对象的key查询值

SELECT info_j -> 'items' ->> 'product' AS customer FROM orders;

解析TEXT中的JSON字段

其实和解析JSON字段一样我们只需要加上::json