基于 SELECT 更新列，参数来自 UPDATE

Question

我想做这样的事情。

UPDATE tbl_states AS ts
SET    tbl_states.country_id = (SELECT tbl_countries.country_id
                                FROM   tbl_states ts1
                                       JOIN tbl_countries
                                         ON tbl_countries.country_id_id =
                                            ts1.country_id
                                WHERE  ts1.country_id_id = ts.country_id_id)  

我想根据插入的新主键将来自不同数据库的旧 country_id 更新为新 country_id新数据库。这里给你一个想法是架构。

CREATE TABLE [dbo].[tbl_countries](
    [country_id] [int] IDENTITY(1,1) NOT NULL,
    [country_id_id] [int] NULL,
    [country_name] [varchar](50) NULL)

country_id_id 是下一个表格中引用的旧 country_id，我将向您展示tbl_states

CREATE TABLE [dbo].[tbl_states](
    [state_id] [int] IDENTITY(1,1) NOT NULL,
    [state_name] [varchar](50) NULL,
    [country_id] [int] NULL,
    [state_abbr] [char](3) NOT NULL)

我想更新使用以下 select 语句将该表的 Country_id 列 tbl_states 复制到上表的主列来获取主键。

SELECT tbl_countries.country_id
FROM   tbl_states_old
       JOIN tbl_countries
         ON tbl_countries.country_id_id = tbl_states_old.country_id  

对不起这个标题，我不知道这个叫什么。你能帮我解决这个问题吗？

Answer 1

UPDATE s
    SET country_id = c.country_id
    FROM tbl_states s
        INNER JOIN tbl_countries c
            ON s.country_id = c.country_id_id