Quiziz SQL

Queremos saber los 5 primeros condados con las mayores poblaciones.

¿Qué consulta(s) sql nos permite responder a esta pregunta?

• SELECT TOP 5 * FROM counties

  ORDER BY population DESC

• SELECT TOP 5 * FROM counties

  ORDER BY DESC population

• SELECT * FROM counties

  ORDER BY population

  LIMIT 5

• SELECT * FROM counties

  ORDER BY population

  LIMIT 5

Queremos saber el número de estados por cada región.

¿Qué consulta(s) sql nos permite responder a esta pregunta?

• SELECT count(DISTINCT state) AS count_state

  FROM counties

• SELECT region, count(state) AS count_state

  FROM counties

  GROUP BY region

• SELECT region, count(DISTINCT state) AS count_state

  FROM counties

  GROUP BY region

• 2 alternativas son correctas.

Queremos saber los votos de cada partido por cada región.

¿Qué consulta(s) sql nos permite responder a esta pregunta?

• SELECT C.region, sum(E.democrat) AS votes_democrat, sum(E.republic) AS votes_republic, sum(E.other) AS votes_other

  FROM counties C

  INNER JOIN elections E

  ON E.codcounty = C.codecounty

• SELECT C.region, sum(E.democrat) AS votes_democrat, sum(E.republic) AS votes_republic, sum(E.other) AS votes_other

  FROM counties C

  INNER JOIN elections E

  ON E.codcounty = C.codecounty

  GROUP BY C.region

• SELECT C.region, sum(E.democrat) AS votes_democrat, sum(E.republic) AS votes_republic, sum(E.other) AS votes_other

  FROM elections E

  LEFT JOIN counties C

  ON E.codcounty = C.codecounty

  GROUP BY C.region

Queremos saber la cantidad de votos de cada partido.

¿Qué consulta(s) sql nos permite responder a esta pregunta?

• SELECT sum(democrat) AS votes_democrat, sum(republic) AS votes_republic, sum(other) AS votes_other

  FROM elections

• SELECT namecounty, sum(democrat) AS votes_democrat, sum(republic) AS votes_republic, sum(other) AS votes_other

  FROM elections

  GROUP BY namecounty

• SELECT sum(democrat, republic, other) AS (votes_democrat, votes_republic, votes_other)

  FROM elections

Queremos saber los votos de cada partido en cada estado que comience en "A". Considerar solo partido republicano y demócrata para esta pregunta.

¿Qué consulta(s) sql nos permite responder a esta pregunta?

• SELECT namecounty, SUM(republic) AS votes_republic, sum(democrat) AS votes_democrat

  FROM elections

  GROUP BY namecounty

  HAVING namecounty LIKE '%A'

• SELECT namecounty, SUM(republic) AS votes_republic, sum(democrat) AS votes_democrat

  FROM elections

  GROUP BY namecounty

  HAVING namecounty LIKE 'A%'

• SELECT namecounty, SUM(republic) AS votes_republic, sum(democrat) AS votes_democrat

  FROM elections

  WHERE namecounty LIKE 'A%'

  GROUP BY namecounty

6) ¿Cuál es la diferencia entre having y where?

• A) WHERE opera sobre registros individuales, mientras que HAVING lo hace sobre un grupo de registros.

• B) HAVING opera sobre registros individuales, mientras que WHERE lo hace sobre un grupo de registros.

• C) HAVING se utiliza para ordenar filas de manera ascendente, mientras que WHERE se utiliza para ordenar filas de manera descendente.

• D) HAVING y WHERE son intercambiables y se pueden usar indistintamente en cualquier consulta SQL sin diferencia real.