Remove duplicate entries / rows a mySQL database table - DeDupe
Before you start - backup your table, do an export with phpmyadmin.
Step 1: Move the non duplicates (unique tuples) into a temporary table
CREATE TABLE new_table AS
SELECT * FROM old_table WHERE 1 GROUP BY [COLUMN TO remove duplicates BY];
Step 2: delete delete the old table
We no longer need the table with all the duplicate entries, so drop it!
DROP TABLE old_table;
Step 3: rename the new_table to the name of the old_table
RENAME
TABLE new_table TO old_table;Now you can fix that buggy code thats causing duplicate entries.
Just use “insert IGNORE into ….” to prevent duplicate entries, or add an “ON DUPLICATE KEY UPDATE …” at the end of your mysql query.
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