How to Merge MySQL Tables with Duplicate Primary Keys?

Resolving Primary Key Conflicts When Merging MySQL Tables

Merging MySQL tables with identical structures but conflicting primary keys requires careful consideration. This guide outlines two effective methods to handle this challenge:

The INSERT IGNORE statement provides a solution where rows from the second table will overwrite existing rows in the first table only if the primary keys match. Rows from the second table with unique primary keys will be inserted into the first table. This approach is demonstrated below:

<code class="language-sql">INSERT IGNORE INTO table_1 SELECT * FROM table_2;</code>

Alternatively, the REPLACE statement offers a different approach. Instead of ignoring duplicates, it updates existing rows in table_1 with matching primary keys from table_2. New rows with unique primary keys are still added. The syntax is as follows:

<code class="language-sql">REPLACE INTO table_1 SELECT * FROM table_2;</code>

Both INSERT IGNORE and REPLACE offer efficient ways to merge tables with duplicate primary keys, ensuring data consolidation while preserving database integrity. Choose the method that best suits your desired outcome – overwriting or updating existing data.

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