教你在PostgreSql中使用JSON字段的方法

CREATE TABLE "public"."biz_orders" (  "ID" int8 NOT NULL DEFAULT nextval('"biz_orders_ID_seq"'::regclass),
  "info" json NOT NULL
);

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

select * from biz_orders;

SELECT info -> 'name' AS customer FROM biz_orders;

SELECT info ->> 'name' AS customer FROM biz_orders;

SELECT
   info -> 'items' ->> 'product' as product
FROM
   biz_orders
ORDER BY
   product;

SELECT
   info ->> 'name' AS customer
FROM
   biz_orders
WHERE
   info -> 'items' ->> 'product' = '辣条'

SELECT
   info ->> 'name' AS customer,
   info -> 'items' ->> 'product' AS product
FROM
   biz_orders
WHERE
   CAST (
      info -> 'items' ->> 'qty' AS INTEGER
   ) = 6

SELECT
  MIN( CAST ( info -> 'items' ->> 'qty' AS INTEGER ) ),
  MAX( CAST ( info -> 'items' ->> 'qty' AS INTEGER ) ),
  SUM( CAST ( info -> 'items' ->> 'qty' AS INTEGER ) ),
  AVG( CAST ( info -> 'items' ->> 'qty' AS INTEGER ) ) 
FROM
  biz_orders;

SELECT
  json_typeof ( info -> 'items' -> 'qty' ) 
FROM
  biz_orders;