sql - psql 你如何从复合数组中选择

Question

CREATE TYPE complex AS (
start_time timestamp,
amount int,
);

给定一个变量

my_complexes complex[]

怎么像查询表一样查询呢？

SELECT amount FROM my_complexes;

给出“关系不存在”。

SELECT mc.amount FROM (SELECT my_complexes) mc;

给出“数量不存在”。

如果相关，my_complexes 将作为函数的参数传入。然后我想在该数组上进行选择。

Answer 1

你应该使用:

SELECT (your_column_from_table_ my_complexes).amount FROM my_complexes;

完整示例:

CREATE TYPE complex AS (
   start_time timestamp,
   amount int
);

CREATE TABLE my_complexes (
    clm complex
);

INSERT INTO my_complexes VALUES ((LOCALTIMESTAMP, 112));
SELECT (clm).amount FROM my_complexes;