根据当前记录更新 table

Question

在我的 PostgreSQL 数据库中，出于各种原因，我正在从整数键转换为 UUID。所以现在我有 table 人和 ident serial primary key，以及 table TeamPerson 和 person_id integer references Person (ident)。

然后我去添加一个 uid UUID 列，其中对 Person 具有唯一约束，并向 TeamPerson 添加一个 person_uid references Person (uid) 列。所以现在我需要让所有 person_uid 对应于 person_id 引用。我想要这样的东西：

UPDATE TeamPerson
SET person_uid = (
    SELECT uid FROM Person WHERE ident = current_team_person_row.person_id
)

current_team_person_row 是我要解决的问题。我想我需要一个带有 WHERE CURRENT OF 的光标，但我只是不知道如何做。

Answer 1

您可能正在寻找：correlated subquery，也称为 "dependent subquery"

In a SQL database query, a correlated subquery (also known as a synchronized subquery) is a subquery (a query nested inside another query) that uses values from the outer query.

UPDATE TeamPerson tp
SET person_uid = (
    SELECT uid FROM Person p 
    WHERE p.ident = tp.person_id
)

根据当前记录更新 table

Update table based on current record

postgresql

cursor

sql-update