What are the advantages and disadvantages of using INNER JOIN versus LEFT JOIN in PHP SQL queries?

When deciding between using INNER JOIN and LEFT JOIN in PHP SQL queries, it's important to consider the data you want to retrieve and how you want to handle missing data. INNER JOIN only returns rows where there is a match in both tables, while LEFT JOIN returns all rows from the left table and the matched rows from the right table. If you want to only retrieve data where there is a match in both tables, use INNER JOIN. If you want to retrieve all data from the left table and include any matching data from the right table (or NULL if there is no match), use LEFT JOIN. 

// Using INNER JOIN
$query = "SELECT * FROM table1 INNER JOIN table2 ON table1.id = table2.id";
$result = mysqli_query($connection, $query);

// Using LEFT JOIN
$query = "SELECT * FROM table1 LEFT JOIN table2 ON table1.id = table2.id";
$result = mysqli_query($connection, $query);

Keywords

INNER JOIN LEFT JOIN SQL queries advantages disadvantages

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