Question

我有一张下表，其中列出了不同的运动方式和运动员的国籍。

CREATE table test
(
    column01 VARCHAR(255),
    column02 VARCHAR(255)
)

INSERT INTO test VALUES('soccer', 'brazilian');
INSERT INTO test VALUES('soccer', 'brazilian');
INSERT INTO test VALUES('soccer', 'argentinian');
INSERT INTO test VALUES('cycling', 'american');
INSERT INTO test VALUES('cycling', 'colombian');
INSERT INTO test VALUES('cycling', 'colombian');
INSERT INTO test VALUES('cycling', 'colombian');
INSERT INTO test VALUES('bascketball', 'american');
INSERT INTO test VALUES('bascketball', 'american');
INSERT INTO test VALUES('bascketball', 'french');
INSERT INTO test VALUES('bascketball', 'spanish');

我想按相同模式的数量以及每种模式的国籍来得到一个结果组。像这样：

column01 | column02
---------+----------
    3    |     2
    4    |     2
    4    |     3

Answer 1

您似乎想要：

select count(*), count(distinct column2)
from t
group by column1;

PostgreSQL按同一表中的两列分组

1 个答案: