统计用户未联系过的组织

Question

我是 PostgreSQL 的新手。我在我的架构中创建了以下 tables：

用户table:

CREATE TABLE public.users
(
    user_id integer NOT NULL DEFAULT nextval('users_user_id_seq'::regclass),
    first_name character varying(90) COLLATE pg_catalog."default" NOT NULL,
    last_name character varying(90) COLLATE pg_catalog."default" NOT NULL,
    email citext COLLATE pg_catalog."default" NOT NULL,
    user_password character varying(90) COLLATE pg_catalog."default" NOT NULL,
    bt_id integer,
    reset_password_token character varying COLLATE pg_catalog."default",
    bstage_id integer,
    CONSTRAINT users_pkey PRIMARY KEY (user_id),
    CONSTRAINT users_email_key UNIQUE (email),
    CONSTRAINT bstage_id FOREIGN KEY (bstage_id)
        REFERENCES public.business_stage (bstage_id) MATCH SIMPLE
        ON UPDATE NO ACTION
        ON DELETE CASCADE,
    CONSTRAINT bt_id FOREIGN KEY (bt_id)
        REFERENCES public.business_type (bt_id) MATCH SIMPLE
        ON UPDATE CASCADE
        ON DELETE CASCADE
        NOT VALID
)
WITH (
    OIDS = FALSE
)

组织table：

CREATE TABLE public.organization
(
    org_id integer NOT NULL DEFAULT nextval('organization_org_id_seq'::regclass),
    name character varying(90) COLLATE pg_catalog."default" NOT NULL,
    description character varying(90) COLLATE pg_catalog."default" NOT NULL,
    email citext COLLATE pg_catalog."default" NOT NULL,
    phone_number character varying(11) COLLATE pg_catalog."default" NOT NULL,
    bt_id integer NOT NULL,
    bs_id integer NOT NULL,
    is_active boolean NOT NULL,
    org_link character varying COLLATE pg_catalog."default",
    CONSTRAINT organization_pkey PRIMARY KEY (org_id),
    CONSTRAINT bs_id FOREIGN KEY (bs_id)
        REFERENCES public.business_step (bs_id) MATCH SIMPLE
        ON UPDATE CASCADE
        ON DELETE CASCADE
        NOT VALID,
    CONSTRAINT bt_id FOREIGN KEY (bt_id)
        REFERENCES public.business_type (bt_id) MATCH SIMPLE
        ON UPDATE CASCADE
        ON DELETE CASCADE
        NOT VALID
)
WITH (
    OIDS = FALSE
)

最后 Organization_rating table:

CREATE TABLE public.organization_rating
(
    rating integer NOT NULL,
    user_id integer NOT NULL,
    organization_id integer NOT NULL,
    rating_comment character varying(255) COLLATE pg_catalog."default",
    CONSTRAINT organization_rating_pkey PRIMARY KEY (user_id, organization_id),
    CONSTRAINT user_id FOREIGN KEY (user_id)
        REFERENCES public.users (user_id) MATCH SIMPLE
        ON UPDATE CASCADE
        ON DELETE CASCADE,
    CONSTRAINT stars CHECK (rating >= 1 AND rating < 5)
)
WITH (
    OIDS = FALSE
)

使用此模式，组织拥有一种业务类型，在该业务类型中为也具有该业务类型的用户提供支持。给予支持后，用户可以给这个组织打分organization_rating。按照这个逻辑，我想执行一个查询，该查询会给出用户已联系评级的组织与用户仍需要评级的组织的百分比。例如，假设 user_id 1 对组织 1 评分，该组织与用户具有相同的业务类型。另有 9 个组织具有相同的业务类型，但用户未对这些组织进行评级。此查询将 return 10%。

我有以下查询来计算用户已经联系过的组织：

Select U.first_name, COUNT(R.rating)
From users as U INNER JOIN organization_rating as R on U.user_id = R.user_id
Inner join organization as O on O.org_id = R.organization_id
Where O.bt_id = 1 AND R.user_id != 62
Group by U.first_name;

如何计算该用户未联系过的组织，以及已联系与仍未联系的百分比？

如果你也能给我介绍一些可以帮助我了解更多 PostgreSQL 和不同功能的网站，我将不胜感激。提前致谢！

Answer 1

您可以 cross join 用途和组织以获得所有可能的组合，然后将桥 table 与 left join 连接起来。最后一步是条件聚合：

SELECT u.first_name, 
    COUNT(*) FILTER (WHERE r.user_id IS NULL) as cnt_not_contacted,
    AVG((r.user_id IS NOT NULL)::int) as avg_contacted
FROM users u
CROSS JOIN organization o
LEFT JOIN organization_rating r ON u.user_id = r.user_id AND o.org_id = r.organization_id
WHERE o.bt_id = 1 AND u.user_id <> 62
GROUP BY u.user_id

统计用户未联系过的组织

Counting organizations which user has not contacted

sql

postgresql

inner-join

count

left-join