Question

这是表格。

!important

我有5000条记录。我想要得到的是以下结果：有57个相机，它们各有不同，但有3个相同，都是

CREATE TABLE cameras
(
  id integer NOT NULL DEFAULT nextval('sq_streams'::regclass),
  created_at timestamp with time zone NOT NULL DEFAULT now(),
  updated_at timestamp with time zone NOT NULL DEFAULT now(),
  exid text NOT NULL,
  owner_id integer NOT NULL,
  is_public boolean NOT NULL,
  config json NOT NULL,
  name text NOT NULL,
  last_polled_at timestamp with time zone DEFAULT now(),
  is_online boolean,
  timezone text,
  last_online_at timestamp with time zone DEFAULT now(),
  location geography(Point,4326),
  mac_address macaddr,
  model_id integer,
  discoverable boolean NOT NULL DEFAULT false,
  preview bytea,
  thumbnail_url text,
  CONSTRAINT pk_streams PRIMARY KEY (id)
)

我想创建一个查询，将结果显示为

'external_http_port', config->> 'external_host', config-> 'snapshots'->> 'jpg'

Answer 1

这是怎么回事？

SELECT config ->>'external_http_port' AS external_http_port, 
       config->> 'external_host' AS external_host, 
       config-> 'snapshots'->> 'jpg' AS snapshots,
       count(*) 
FROM cameras  
GROUP BY config->>'external_http_port', config->> 'external_host', config-> 'snapshots'->> 'jpg' 
HAVING count(*) > 1;

Answer 2

它能解决这个问题吗？（想象一个类比，而不是文字）

double units

PostgreSQL - 根据3列选择重复数据

2 个答案: