What are the potential pitfalls when comparing data records from two tables in PHP?

When comparing data records from two tables in PHP, potential pitfalls include differences in data types, missing or duplicate records, and varying column names. To solve this, it's important to ensure that the data being compared is of the same type, handle any missing or duplicate records appropriately, and use aliases or mapping to compare columns with different names. 

// Example code snippet to compare data records from two tables in PHP
$connection = new mysqli("localhost", "username", "password", "database");

// Fetch records from table1
$query1 = "SELECT * FROM table1";
$result1 = $connection->query($query1);
$data1 = [];
while ($row = $result1->fetch_assoc()) {
    $data1[] = $row;
}

// Fetch records from table2
$query2 = "SELECT * FROM table2";
$result2 = $connection->query($query2);
$data2 = [];
while ($row = $result2->fetch_assoc()) {
    $data2[] = $row;
}

// Compare data records from both tables
foreach ($data1 as $record1) {
    foreach ($data2 as $record2) {
        if ($record1['column1'] == $record2['column2']) {
            // Perform comparison logic here
        }
    }
}

Keywords

data comparison SQL queries database tables data validation error handling

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