ALTER [IGNORE] TABLE table changes[, ...]

Use this statement to change an existing table’s structure and other properties. A table may be altered with this statement in the following ways:

The IGNORE flag applies to all clauses and instructs MySQL to ignore any error messages regarding duplicate rows that may occur as a result of a column change. It will keep the first unique row found and drop any duplicate rows. Otherwise, the statement will be terminated and changes will be rolled back.

This statement requires the ALTER, CREATE, and INSERT privileges for the table being altered, at a minimum. While an ALTER TABLE statement ...

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