Examine A Query

Create Table

-- Create table called adventurers
CREATE TABLE adventurers (
    -- string variable
    name varchar(255),
    -- integer variable
    age int,
    -- string variable
    race varchar(255),
    -- string variable
    weapon varchar(255)
)

Insert Row

-- Insert into the table adventurers
INSERT INTO adventurers (name, age, race, weapon)
VALUES ('Fjoak Doom-Wife', 28, 'Human', 'Axe'),
       ('Alooneric Cortte', 29, 'Elf', 'Bow'),
       ('Piperel Ramsay', 35, 'Elf', 'Sword'),
       ('Casimir Yardley', 14, 'Elf', 'Magic')

View Table

-- Retrieve rows from table
SELECT * FROM adventurers
nameageraceweapon
Fjoak Doom-Wife28HumanAxe
Alooneric Cortte29ElfBow
Piperel Ramsay35ElfSword
Casimir Yardley14ElfMagic

Examine Query

Note: the lower the cost the better.

-- Examine the query: retrieve all rows from table
EXPLAIN SELECT * FROM adventurers
QUERY PLAN
Seq Scan on adventurers (cost=0.00..10.50 rows=50 width=1552)