0
In this consultation I would use the GROUP BY?
That and the model 
1 answer
2
Translate the table Aluno of its model to PL/PgSQL:
CREATE TABLE Aluno
(
idaluno BIGINT PRIMARY KEY,
nome TEXT NOT NULL,
cpf VARCHAR(11) NOT NULL,
rg VARCHAR(14) NOT NULL,
sexo VARCHAR(1) NOT NULL,
data_nascimento DATE NOT NULL
);
Registering Students:
INSERT INTO Aluno ( idaluno, nome, cpf, rg, sexo, data_nascimento ) VALUES
( 100, 'JOAO', '11122233300', '1234567', 'M', '1980-03-10' ),
( 200, 'JESUS', '99988877766', '45678', 'M', '1970-06-17' ),
( 300, 'MARIA', '44455566677', '09876', 'F', '1953-04-30' ),
( 400, 'MADALENA', '33399955511', '345677', 'F', '1965-10-23' ),
( 500, 'JOSE', '00987243643', '8181818', 'M', '1988-03-03' );
Solution #1: With GROUP BY and count():
SELECT
sexo,
COUNT(1)
FROM
Aluno
GROUP BY
sexo;
Exit:
| sexo | count |
|------|-------|
| F | 2 |
| M | 3 |
Solution #2: With sum() and without GROUP BY:
SELECT
SUM(CASE WHEN sexo = 'M' THEN 1 ELSE 0 END) AS qtd_masculino,
SUM(CASE WHEN sexo = 'F' THEN 1 ELSE 0 END) AS qtd_feminino,
SUM(1) AS qtd_total
FROM
Aluno;
Exit:
| qtd_masculino | qtd_feminino | qtd_total |
|---------------|--------------|-----------|
| 3 | 2 | 5 |
Sqlfiddle: http://sqlfiddle.com/#! 17/557d1/2
Browser other questions tagged sql database postgresql
You are not signed in. Login or sign up in order to post.
Yes, with group by. Have you tried something? If yes, post in the question the query and the results you got.
– Woss
Do you want the number of students enrolled in some course of some discipline, or all students independent of that? Etc...
– David