检查 MySQL 条目是否存在，如果存在，则覆盖其他列

Question

I have a MySQL table set out as the following

UID | Thing1 | Thing2 | Date

The UID column has been set as unique and is made from the users ID + the date as an integer. IE 7620150715

What I'd like to do is check to see if the UID exists, if it does, then update columns thing1 and thing2 with the latest information.

If the UID doesn't exist, then create a new row for all the information.

Currently, what works to enter is

$sql = "INSERT INTO things2 (uid, thing1, thing2, date) VALUES (:uid, :thing1,:thing2,:date)";

But this doesn't work after making UID unique.

I've found that the ON DUPLICATE KEY UPDATE statement seems to be what I'm looking for, but all answers appear to be adding +1 to the input, which is not what I want to do.

Some pseudo syntax for what I'm looking for would go like this

$sql = "INSERT INTO things2 (uid, thing1, thing2, date) VALUES (:uid, :thing1,:thing2,:date ON DUPLICATE KEY UPDATE (thing1, thing2) VALUES (:thing1, :thing2)";

What would be the correct syntax?

Answer 1

The easiest/most clear way needs two steps:

First do an INSERT OR IGNORE of just the (new) UID. Don't bother with the values yet, because you will update anyway. Just make sure that table allows this with proper defaults and not too many constraints:

INSERT OR IGNORE INTO things2 (uid) VALUES (:uid)

Then do an UPDATE ... SET a=b WHERE UID=.. to actually update the records:

UPDATE thing1=:thing1, thing2=:thing2 WHERE UID = :uid

(Not tested, and please check because I am more into C++/sqlite than in MySql/php)

Answer 2

Your syntax is a little wrong. If the INSERT fails then you code an UPDATE with the standard UPDATE syntax like so.

$sql = "INSERT INTO things2 
               (uid, thing1, thing2, `date`) 
        VALUES (:uid, :thing1,:thing2,:date )
        ON DUPLICATE KEY 
        UPDATE things2 SET thing1 = :thing1, thing2 = :thing2, `date` = :date";

Also date is a reserved word so its best to wrap it in backticks.