Why are duplicate rows inserted in MySQL?
Well, using IGNORE is what I learned from another mysql website: “And when you insert, you can use INSERT IGNORE INTO … so it ignores duplicates instead of throwing an error. (Useful when batch inserting and expecting duplicates)” Just want to make sure I’m on the right track.
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What is the last insert id in MySQL in duplicate key?
If you have an auto-incrementing package and a unique key on, say, an email address, and the ‘on duplicate update’ triggers are based on the email address, note that last_insert_id’ will NOT be the value of auto increment the updated row. It appears to be the most recently inserted auto-increment value. This makes a huge difference.
What happens when you insert a new row in MySQL?
When inserting a new row into a table if the row results in a duplicate at the UNIQUE index or PRIMARY KEY, MySQL will throw an error. However, if you specify the ON DUPLICATE KEY UPDATE option in the INSERT statement, MySQL will update the existing row with the new values instead.
How does duplicate key update work in MySQL?
ON DUPLICATE KEY UPDATE will only update the columns you specify and keep the row. REPLACE works exactly like INSERT, except that if a previous row in the table has the same value as a new row for a PRIMARY KEY or UNIQUE index, the previous row is deleted before the new row is inserted. Existing solutions work if you use autoincrement.
When to insert a new row in a table in MySQL?
When inserting a new row into a table if the row results in a duplicate at the UNIQUE index or PRIMARY KEY, MySQL will throw an error. However, if you specify the ON DUPLICATE KEY UPDATE option in the INSERT statement, MySQL will update the existing row with the new values instead. The syntax of the INSERT ON DUPLICATE KEY UPDATE statement is as follows:
How to insert in duplicate key update in MySQL?
INSERT INTO ON DUPLICATE KEY UPDATE will only work for MYSQL, not SQL Server. You can use Replace instead of INSERT IN DUPLICATE KEY UPDATE. Yes, but when using REPLACE, the old row is removed before the new row is inserted. I want to keep the previous row to keep the parent ids. — Prashant Apr 26
How to check mysql table on multiple columns?
The query to create a table is as follows. Insert some records into the table using the insert command. The query is the following. Show all the records in the table using the select statement. Next is the output. Here is the query to check the table for duplicates.