MySQL: Insert data into table, some data comes from another table (relational)

问题

I want to run the following two queries in one:

SELECT id FROM user_settings WHERE ......
$id = id_from_query_above();
$value = 100; // this could be anything
INSERT INTO user_config (sid, value) VALUES($id, $value) ON DUPLICATE KEY UPDATE value=$value

(notice that I want to update if a row associating to the primary key has already been inserted).

回答1:

You want the insert . . . select syntax:

INSERT INTO user_config(sid, value)
    SELECT id, $value
    FROM user_settings
    WHERE ......
    ON DUPLICATE KEY UPDATE value = $value;

来源：https://stackoverflow.com/questions/24816260/mysql-insert-data-into-table-some-data-comes-from-another-table-relational