PHP mysqli: query() function
mysqli_query() function / mysqli::query
The mysqli_query() function / mysqli::query performs a query against the database.
Syntax:
Object oriented style
mixed mysqli::query ( string $query [, int $resultmode = MYSQLI_STORE_RESULT ] )
Procedural style
mixed mysqli_query ( mysqli $link , string $query [, int $resultmode = MYSQLI_STORE_RESULT ] )
Parameter:
| Name | Description | Required/Optional |
|---|---|---|
| link | A link identifier returned by mysqli_connect() or mysqli_init() | Required for procedural style only and Optional for Object oriented style |
| query | The query string. Data inside the query should be properly escaped. |
Required for procedural style only and Optional for Object oriented style |
| resultmode | Either the constant MYSQLI_USE_RESULT or MYSQLI_STORE_RESULT depending on the desired behavior. By default, MYSQLI_STORE_RESULT is used. If you use MYSQLI_USE_RESULT all subsequent calls will return error Commands out of sync unless you call mysqli_free_result() With MYSQLI_ASYNC (available with mysqlnd), it is possible to perform query asynchronously. mysqli_poll() is then used to get results from such queries. |
Optional |
Usage: Procedural style
mysqli_query(connection,query,resultmode);
Parameter:
| Name | Description | Required / Optional |
|---|---|---|
| connection | Specifies the MySQL connection to use | Required |
| query | Specifies the query string | Required |
| resultmode | A constant. Either:
|
Optional |
Return value:
Returns FALSE on failure. For successful SELECT, SHOW, DESCRIBE or EXPLAIN queries mysqli_query() will return a mysqli_result object. For other successful queries mysqli_query() will return TRUE.
Version: PHP 5, PHP 7
Example of object oriented style:
<?php
$mysqli = new mysqli("localhost", "user1", "datasoft123", "hr");
/* check connection */
if ($mysqli->connect_errno) {
printf("Connect failed: %s\n", $mysqli->connect_error);
exit();
}
/* Create table doesn't return a resultset */
if ($mysqli->query("CREATE TEMPORARY TABLE myCity LIKE City") === TRUE) {
printf("Table myCity successfully created.\n");
}
/* Select queries return a resultset */
if ($result = $mysqli->query("SELECT Name FROM City LIMIT 10")) {
printf("Select returned %d rows.\n", $result->num_rows);
/* free result set */
$result->close();
}
/* If we have to retrieve large amount of data we use MYSQLI_USE_RESULT */
if ($result = $mysqli->query("SELECT * FROM City", MYSQLI_USE_RESULT)) {
/* Note, that we can't execute any functions which interact with the
server until result set was closed. All calls will return an
'out of sync' error */
if (!$mysqli->query("SET @a:='this will not work'")) {
printf("Error: %s\n", $mysqli->error);
}
$result->close();
}
$mysqli->close();
?>
Example of procedural style:
<?php
$link = mysqli_connect("localhost", "user1", "datasoft123", "hr");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* Create table doesn't return a resultset */
if (mysqli_query($link, "CREATE TEMPORARY TABLE myCity LIKE City") === TRUE) {
printf("Table myCity successfully created.\n");
}
/* Select queries return a resultset */
if ($result = mysqli_query($link, "SELECT Name FROM City LIMIT 10")) {
printf("Select returned %d rows.\n", mysqli_num_rows($result));
/* free result set */
mysqli_free_result($result);
}
/* If we have to retrieve large amount of data we use MYSQLI_USE_RESULT */
if ($result = mysqli_query($link, "SELECT * FROM City", MYSQLI_USE_RESULT)) {
/* Note, that we can't execute any functions which interact with the
server until result set was closed. All calls will return an
'out of sync' error */
if (!mysqli_query($link, "SET @a:='this will not work'")) {
printf("Error: %s\n", mysqli_error($link));
}
mysqli_free_result($result);
}
mysqli_close($link);
?>
Output:
Table myCity successfully created. Select returned 10 rows. Error: Commands out of sync; You can't run this command now
See also
Previous: prepare
Next: real_connect