MySQL Reference

mysqli_connect(host, user, password, database) → Opens a MySQL connection.

$conn = mysqli_connect("localhost","root","","test"); → Example connection.

mysqli_connect_error() → Returns last connection error.

mysqli_close($conn) → Closes database connection.

mysqli_query($conn, $sql) → Executes SQL query.

$res = mysqli_query($conn,"SELECT * FROM users"); → Example SELECT query.

mysqli_affected_rows($conn) → Number of rows changed by INSERT/UPDATE/DELETE.

mysqli_insert_id($conn) → Last inserted ID.

mysqli_fetch_assoc($res) → Fetch row as associative array.

mysqli_fetch_row($res) → Fetch row as numeric array.

mysqli_fetch_array($res) → Fetch row as both assoc + numeric.

mysqli_num_rows($res) → Number of rows in result.

mysqli_free_result($res) → Frees memory of result.

mysqli_prepare($conn, $sql) → Prepares SQL statement.

$stmt = mysqli_prepare($conn,"SELECT * FROM users WHERE id=?"); → Example prepare.

mysqli_stmt_bind_param($stmt,"i",$id) → Binds variable to statement.

i → integer type.

d → double type.

s → string type.

b → blob type.

mysqli_stmt_execute($stmt) → Executes prepared statement.

mysqli_stmt_get_result($stmt) → Gets result set.

mysqli_stmt_fetch($stmt) → Fetches prepared row.

mysqli_stmt_close($stmt) → Closes statement.

mysqli_begin_transaction($conn) → Starts transaction.

mysqli_commit($conn) → Saves changes.

mysqli_rollback($conn) → Cancels changes.

mysqli_error($conn) → Last error message.

mysqli_errno($conn) → Last error code.

mysqli_stmt_error($stmt) → Statement error.

mysqli_real_escape_string($conn,$str) → Escapes special characters.

Prepared statements → Prevent SQL injection.

SELECT * FROM table → Reads data.

INSERT INTO table(col) VALUES(val) → Inserts data.

UPDATE table SET col=val → Updates data.

DELETE FROM table WHERE id=1 → Deletes data.