mysqli::query
mysqli_query
(PHP 5, PHP 7)
mysqli::query -- mysqli_query — 对数据库执行一次查询
说明
面向对象风格
过程化风格
Performs a query against the database.
For non-DML queries (not INSERT, UPDATE or DELETE), this function is similar to calling mysqli_real_query() followed by either mysqli_use_result() or mysqli_store_result().
Note:
In the case where you pass a statement to mysqli_query() that is longer than max_allowed_packet of the server, the returned error codes are different depending on whether you are using MySQL Native Driver (mysqlnd) or MySQL Client Library (libmysqlclient). The behavior is as follows:
mysqlnd on Linux returns an error code of 1153. The error message means
got a packet bigger than max_allowed_packet bytes.mysqlnd on Windows returns an error code 2006. This error message means
server has gone away.libmysqlclient on all platforms returns an error code 2006. This error message means
server has gone away.
参数
-
link -
仅以过程化样式：由mysqli_connect() 或 mysqli_init() 返回的链接标识。
-
query -
The query string.
Data inside the query should be properly escaped.
-
resultmode -
Either the constant
MYSQLI_USE_RESULTorMYSQLI_STORE_RESULTdepending on the desired behavior. By default,MYSQLI_STORE_RESULTis used.If you use
MYSQLI_USE_RESULTall 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.
返回值
失败时返回 FALSE，通过mysqli_query() 成功执行SELECT, SHOW, DESCRIBE或 EXPLAIN查询会返回一个mysqli_result 对象，其他查询则返回TRUE。
更新日志
| 版本 | 说明 |
|---|---|
| 5.3.0 | Added the ability of async queries. |
范例
Example #1 mysqli::query() example
面向对象风格
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if ($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();
?>
过程化风格
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* Create table doesn't return a resultset */
if (mysqli_query($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);
?>
以上例程会输出：
Table myCity successfully created. Select returned 10 rows. Error: Commands out of sync; You can't run this command now
参见
- mysqli_real_query() - 执行一个mysql查询
- mysqli_multi_query() - 执行查询
- mysqli_free_result() - Frees the memory associated with a result
