MySQL：仅在插入时插入

Question

我想仅在查询的两个值（或更多）不同时才插入行：

INSERT INTO table (id, title, description) 
VALUES(1, 'hello', 'world') 
ONLY IF title AND description DOESN't ALREADY EXISTS

Answer 1

INSERT INTO TABLE (ID, TITLE, DESCRIPTION) VALUES (1, 'hello', 'world')
WHERE (SELECT COUNT(ID) FROM TABLE WHERE TITLE='hello' AND DESCRIPTION='world') = 0

Answer 2

如果您在两列

上添加唯一键，我认为您可以使用replace into

REPLACE INTO table (id, title, description) 
VALUES(1, 'hello', 'world')