创建临时表
CREATE TEMP TABLE pivot(
gid SERIAL,
zoom smallint NOT NULL,
day timestamp with time zone NOT NULL,
point integer NOT NULL
);
插入数据
INSERT INTO pivot(zoom, day, point) VALUES(6,'2015-10-01',21);
INSERT INTO pivot(zoom, day, point) VALUES(7,'2015-10-01',43);
INSERT INTO pivot(zoom, day, point) VALUES(8,'2015-10-01',18);
INSERT INTO pivot(zoom, day, point) VALUES(9,'2015-10-01',14);
INSERT INTO pivot(zoom, day, point) VALUES(10,'2015-10-01',23);
INSERT INTO pivot(zoom, day, point) VALUES(11,'2015-10-01',54);
INSERT INTO pivot(zoom, day, point) VALUES(6,'2015-10-02',657);
INSERT INTO pivot(zoom, day, point) VALUES(7,'2015-10-02',432);
INSERT INTO pivot(zoom, day, point) VALUES(8,'2015-10-02',421);
INSERT INTO pivot(zoom, day, point) VALUES(9,'2015-10-02',432);
INSERT INTO pivot(zoom, day, point) VALUES(10,'2015-10-02',454);
INSERT INTO pivot(zoom, day, point) VALUES(11,'2015-10-02',654);
让我们看看到目前为止是否一切正常:
SELECT zoom, day, point
FROM pivot
ORDER BY 1,2;
结果:
zoom | day | point
------+------------------------+-------
6 | 2015-10-01 00:00:00+02 | 21
6 | 2015-10-02 00:00:00+02 | 657
7 | 2015-10-01 00:00:00+02 | 43
7 | 2015-10-02 00:00:00+02 | 432
8 | 2015-10-01 00:00:00+02 | 18
8 | 2015-10-02 00:00:00+02 | 421
9 | 2015-10-01 00:00:00+02 | 14
9 | 2015-10-02 00:00:00+02 | 432
10 | 2015-10-01 00:00:00+02 | 23
10 | 2015-10-02 00:00:00+02 | 454
11 | 2015-10-01 00:00:00+02 | 54
11 | 2015-10-02 00:00:00+02 | 654
(12 rows)
创建扩展:
CREATE EXTENSION tablefunc;
交叉查询
SELECT * FROM crosstab(
'SELECT zoom, day, point
FROM pivot
ORDER BY 1,2'
,$$VALUES ('2015-10-01'::timestamp), ('2015-10-02')$$)
AS ct ("zoom" smallint, "2015-10-01" integer, "2015-10-02" integer);
结果:
zoom | 2015-10-01 | 2015-10-02
------+------------+------------
6 | |
7 | |
8 | |
9 | |
10 | |
11 | |
(6 rows)
我无法返回点的值,查询本身给了我一个空点。我做错了什么?
编辑
我试着用另一种方式去做,但我仍在寻找上述问题的答案。
SELECT * from crosstab (
'select zoom, day, point
from pivot
order by 1,2',
'select distinct day from pivot order by 1')
AS ct(zoom smallint, "2015-10-01" integer, "2015-10-02" integer);
结果:
zoom | 2015-10-01 | 2015-10-02
------+------------+------------
6 | 21 | 657
7 | 43 | 432
8 | 18 | 421
9 | 14 | 432
10 | 23 | 454
11 | 54 | 654
(6 rows)
最佳答案
感谢@Abelisto 关于timestamptz
的建议,这可行:
SELECT * FROM crosstab(
'SELECT zoom, day, point
FROM pivot
ORDER BY 1,2'
,$$VALUES ('2015-10-01'::timestamptz), ('2015-10-02')$$)
AS ct ("zoom" smallint, "2015-10-01" integer, "2015-10-02" integer);
关于postgresql - 如何在 PostgreSQL 中制作交叉表?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/39969520/