存在如下SQL查询:
问题A:发生了什么事?
SELECT
user,
color_id_array
FROM
relation;
结果A:
user, color_id_array
john, [1, 2]
bob, [2, 2, 2]
amy, [2, 2, 3]
查询B:
SELECT
inf_name,
inf_code
FROM
infomation;
结果B:
inf_code, inf_name
1, red
2, green
3, blue
结果A中的COLOR_ID_ARRAY是一个允许重复元素的array.如何创建查询以获得以下输出?正在使用的数据库是PostgreSQL.
请注意,情况并非如此.
user, color_id_array, color_name_array
john, [1, 2], ["red", "green"]
bob, [2, 2, 2], ["green", "green", "green"]
amy, [2, 2, 3], ["green", "green", "blue"]