本文介绍了获取所有唯一记录及其对应的列的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
是否可以在数据库中获取所有唯一记录及其对应的列?
Is it possible to get all unique records as well as their corresponding column in a database?
类似:
SELECT DISTINCT *
FROM table_name
?where?
我想获取所有唯一记录及其对应的列.
I want to get all unique records with their corresponding column.
我试过了:
SELECT distinct(column_name), other_column
FROM table_name
?where?
我仍然收到重复的记录.
I still get duplicate records.
我试过了:
SELECT distinct(column_name)
FROM table_name
?where?
我得到唯一记录但不完整的列.如何获取所有带有列的唯一记录?
I get unique records but incomplete column. How can I get all unique records w/ their column?
推荐答案
您在寻找这样的东西吗?
Are you looking for something like this?
SELECT t.*
FROM
(
SELECT MIN(pk_id) pk_id
FROM table_name
GROUP BY fk_id
) q JOIN table_name t
ON q.pk_id = t.pk_id
这是SQLFiddle演示
Here is SQLFiddle demo
在 Postgres 中你可以使用 DISTINCT ON
In Postgres you can use DISTINCT ON
SELECT DISTINCT ON (fk_id) t.*
FROM table_name t
ORDER BY fk_id
这是SQLFiddle 演示
Here is SQLFiddle demo
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