mysql - 我怎样才能组合这些 SQL 查询以提高 MySQL 的效率？

Question

我有以下查询，我想将它们组合成一个或两个更大的查询:

SELECT user, password, email FROM users WHERE user = 'njp316' LIMIT 1;

INSERT IGNORE INTO collectors_users (username, password, email, dateadded, subscribed)
VALUES (user, password, email, NOW(), 'Y');

这个会拉回多行，所以需要循环:

SELECT barcode FROM collections WHERE user = user;

INSERT IGNORE INTO collections_collections (username, barcode)
VALUES (user, barcode);

显然，我对 SQL 不是很了解，所以只是寻求帮助。谢谢。

Answer 1

除非我遗漏了什么……这很简单:

INSERT IGNORE INTO collectors_users
(username, password, email, dateadded, subscribed)
SELECT user, password, email, NOW(), 'Y'
FROM users 
WHERE user = 'njp316' 
LIMIT 1;

INSERT IGNORE INTO collections_collections 
(username, barcode)
SELECT user, barcode 
FROM collections 
WHERE user = user;