Question

Given the table creation SQL and insertion SQL, How will I generate a query to display the information in a a particular way?

CREATE TABLE cities (
   id serial NOT NULL UNIQUE PRIMARY KEY,
   iname varchar(100) NOT NULL UNIQUE
)

CREATE TABLE suburbs (
    id serial NOT NULL UNIQUE PRIMARY KEY,
    icity integer REFERENCES cities (id), 
    iname varchar(100) NOT NULL UNIQUE
)
CREATE TABLE type (
   id serial NOT NULL UNIQUE PRIMARY KEY,
   iname varchar(100) NOT NULL UNIQUE
)
CREATE TABLE sale (
   id serial NOT NULL UNIQUE PRIMARY KEY,
   iname varchar(100) NOT NULL UNIQUE
)

CREATE TABLE estate (
    id serial NOT NULL UNIQUE PRIMARY KEY,
    icity integer REFERENCES cities (id),
    isuburb integer REFERENCES suburbs (id),
    itype integer REFERENCES type (id),
    isale integer REFERENCES sale (id),
    idescription text,
    itimestamp timestamp DEFAULT CURRENT_TIMESTAMP
)

INSERT INTO cities (iname) VALUES ('Johannesburg');
INSERT INTO suburbs (icity, iname) VALUES (1, 'Westbury');
INSERT INTO type (iname) VALUES ('Room');
INSERT INTO sale (iname) VALUES ('Rent');

INSERT INTO estate (icity, isuburb, itype, isale, idescription) VALUES (1, 1, 1, 1, 'A Nice place in a real bad neighbor hood');

Now I want the numerical values that are in the table estate to be displayed by the string values that they represent.

E.G
1 Johannesburg, Westbury, Room, Rent, Description

What will the SQL Query be for this, I am more concerned in using postgreSQL.

Answer 1

First, they must have some sort of common field. Let’s assume the common field between them is called <tablename>_ID; the way you do it is as follows:

select A.colx, A.coly, A.colz, B.colx, B.colw, c.cold 
from A inner join B on A.ID=B.A_ID 
     inner join C on C.A_ID=A.ID