mysql - MySQL Insert 如果不存在，否则返回 id

Question

我有以下查询；

INSERT INTO table (full_name)
SELECT * FROM (SELECT 'John') AS tmp
WHERE NOT EXISTS (
    SELECT * FROM table WHERE full_name = 'John'
) LIMIT 1;

SELECT id FROM table WHERE full_name = 'John';

它有效，但如您所见，查询分为两部分。只能在单个查询中完成吗？

full_name如果它不存在，我想插入一个新的。否则，返回id现有的full_name。

标签： mysql

Answer 1

您可以使用串联来做到这一点。

$sql = INSERT INTO table (full_name)
SELECT * FROM (SELECT 'John') AS tmp
WHERE NOT EXISTS (
    SELECT * FROM table WHERE full_name = 'John'
) LIMIT 1;

$sql .= SELECT id FROM table WHERE full_name = 'John';