If you specify the IGNORE keyword in an INSERT statement, errors that occur while executing the statement are treated as warnings instead. For example, without IGNORE, a row that duplicates an existing UNIQUE index or PRIMARY KEY value in the table causes a duplicate-key error and the statement is aborted. With IGNORE, the error is ignored and the row is not inserted. Data conversions that would trigger errors abort the statement if IGNORE is not specified. With IGNORE, invalid values are adjusted to the closest value values and inserted; warnings are produced but the statement does not abort. You can determine with the mysql_info() C API function how many rows were inserted into the table.