As with any database operation, understanding the features-and their potential pitfalls-is key to using them effectively. By leveraging the techniques discussed in this article, you can maintain data integrity and avoid redundancy with ease. The ON DUPLICATE KEY UPDATE clause in MySQL is a powerful tool for managing insert operations that would otherwise result in duplication. I have a SQL query where I want to insert multiple rows in single query. MySQL ON DUPLICATE KEY UPDATE for multiple rows insert in single query. ) ON DUPLICATE KEY UPDATE column1 newvalue1, column2 newvalue2. Here’s the syntax of INSERT ON DUPLICATE KEY UPDATE statement: INSERT INTO tablename (column1, column2. Also, be aware of potential race conditions when working with concurrent database access. sql - MySQL ON DUPLICATE KEY UPDATE for multiple rows insert in single query - Stack Overflow. This INSERT ON DUPLICATE KEY UPDATE statement is useful when you deal with unique constraints or primary keys. When using ON DUPLICATE KEY UPDATE, consider the performance implications and ensure that you have proper indexes in place to make the most of its efficiency. If the ‘charlie’ row exists, the email is updated and the LAST_INSERT_ID() function ensures that the AUTO_INCREMENT value remains consistent. It was introduced in MySQL 4. The ON DUPLICATE KEY UPDATE clause works seamlessly with AUTO_INCREMENT columns: INSERT INTO users (username, email) VALUES ('charlie', ' ') MySQL INSERT ON DUPLICATE KEY UPDATE is very powerful but often forgotten MySQL feature.

ON DUPLICATE KEY UPDATE and AUTO_INCREMENT columns on duplicate key update membmemberid ‘STRES17N’, membteamid ‘SK’ only the original membmember id might be ‘SKRES17N’ so as you can see id like to be able to say where membmemberid ‘SKRES17N’ for the cases when its true. If ‘alice’ or ‘bob’ exists in the database, their emails will be updated otherwise, new records will be added. You can also apply ON DUPLICATE KEY UPDATE to multiple-row inserts, as shown: INSERT INTO users (username, email) VALUES Using INSERT … ON DUPLICATE KEY UPDATE with Multiple Rows Here, if ‘joe_doe’ already exists, his score is incremented by 10, and his email is updated. The following example demonstrates such usage: INSERT INTO users (username, email, score) VALUES('joe_doe', ' ', 10) insert() if a row with the corresponding onConflict columns. upsert() allows you to perform the equivalent of. ON DUPLICATE KEY UPDATE also supports the usage of more complex expressions and functions. Depending on the column(s) passed to onConflict. This example updates both the email and created_at columns if a record for ‘jane_doe’ exists and sets conditions for when to update each field.

Manually check and correct the problematic topics (which content may be inconsistent), by visiting /t/topic/274 and others.Next, let’s look at an advanced example where conditionals and multiple columns come into play: INSERT INTO users (username, email, created_at) VALUES ('jane_doe', ' ', NOW())Įmail = IF(VALUES(email) != email, VALUES(email), email),Ĭreated_at = IF(VALUES(created_at) > created_at, VALUES(created_at), created_at).

:ĭiscourse=# update topic_links set url=REPLACE(url, '', '/') where topic_id=274

on error : force a replacement that don’t break unicity, e.g.

try to directly replace url in the tableĭiscourse=# update topic_links set url=REPLACE(url, '', '') ĮRROR: duplicate key value violates unique constraint 'unique_post_links'.

This statement updates the data if any UNIQUE KEY (including the primary key) conflicts. To overcome it, I was unable to launch something like db:exec to force db commands via rake. Use INSERT ON DUPLICATE KEY UPDATE only for a table with one unique key.

I guess the bug is related to the fact that the new domain has been discussed on the forum. It seemed it looked like to the error reported here, but was slightly different. The remap has only been partially applied due to the error above. In posting my question, I thought to make it as simple as possible to focus on the core challenge. This Insert subclass adds a new method Insert. THIS TASK WILL REWRITE DATA, ARE YOU SURE (type YES)Įrror: ERROR: duplicate key value violates unique constraint 'unique_post_links'ĭETAIL: Key (topic_id, post_id, url)=(274, 455, ) already exists. Support for INSERT.ON DUPLICATE KEY UPDATE¶ The ON DUPLICATE KEY UPDATE clause of INSERT supported by MySQL is now supported using a MySQL-specific version of the Insert object, via .insert(). Things looked right until I launched the command discourse remap I tried to change a discourse domain name, following Change the domain name or rename your Discourse.

On duplicate key update