How can the error "SQL Fehler (1062): Duplicate entry '0' for key 'PRIMARY'" be resolved when copying a column between tables in PHP?

The error "SQL Fehler (1062): Duplicate entry '0' for key 'PRIMARY'" occurs when trying to copy a column between tables in PHP and there are duplicate entries in the primary key column. To resolve this issue, you can include a condition to exclude the duplicate entries when copying the column data. 

<?php
// Assuming $sourceTable and $destinationTable are the source and destination tables respectively
$sourceColumn = 'source_column';
$destinationColumn = 'destination_column';

$sql = "INSERT INTO $destinationTable ($destinationColumn) 
        SELECT $sourceColumn FROM $sourceTable 
        WHERE $sourceColumn NOT IN (SELECT $destinationColumn FROM $destinationTable)";

// Execute the SQL query
$result = mysqli_query($connection, $sql);

if($result){
    echo "Column copied successfully!";
} else {
    echo "Error copying column: " . mysqli_error($connection);
}
?>

Keywords

PHP SQL Duplicate entry Primary key Copy column

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