需要帮助简单的sql添加记录

Question

We use (INSERT INTO) to insert a record in the table which creates more than one record when used again. Is there any way to add a record and alternately replacing the prevoius one without adding any new record. I know this would work:

UPDATE Customers
SET ContactName='Alfred Schmidt', City='Hamburg'
WHERE CustomerName='Alfreds Futterkiste';

But what if there is no condition ie. we don't know the record, we only know the column name. Is there any way to fill only one record and alternately replace the previous record without creating 2nd record?

Answer 1

I got my answer and It's working now! I used:

INSERT INTO data (a, b, c)
VALUES
('1','2','3')
ON DUPLICATE KEY UPDATE c=VALUES(a)+VALUES(b)