php mysql_query what does it mean?

php mysql_query is a built-in function in PHP used to execute a MySQL query. The syntax of this function is "mysql_query(query,connection)", where the parameter query represents the SQL query to be sent.

The operating environment of this article: Windows7 system, PHP7.1 version, DELL G3 computer

php What does mysql_query mean?

The mysql_query() function executes a MySQL query.

Syntax

mysql_query(query,connection)

Parameters

query required. Specifies the SQL query to be sent. Note: The query string should not end with a semicolon.

connection Optional. Specifies the SQL connection identifier. If not specified, the last opened connection is used.

Description

If there is no open connection, this function will try to call the mysql_connect() function without parameters to establish a connection and use it.

Return value

mysql_query() returns a resource identifier only for SELECT, SHOW, EXPLAIN or DESCRIBE statements, or FALSE if the query is executed incorrectly.

For other types of SQL statements, mysql_query() returns TRUE when executed successfully and FALSE when an error occurs.

A non-FALSE return value means the query is valid and can be executed by the server. This does not say anything about the number of rows affected or returned. It's possible that a query executed successfully but did not affect or return any rows.

Note: This function automatically reads and caches the record set. To run uncached queries, use mysql_unbuffered_query().

Example

Example 1

<?php
$con = mysql_connect("localhost","mysql_user","mysql_pwd");
if (!$con)
  {
  die(&#39;Could not connect: &#39; . mysql_error());
  }
$sql = "SELECT * FROM Person";
mysql_query($sql,$con);
// 一些代码
mysql_close($con);
?>

Example 2

Create a new database through the mysql_query() function:

<?php
$con = mysql_connect("localhost","mysql_user","mysql_pwd");
if (!$con)
  {
  die(&#39;Could not connect: &#39; . mysql_error());
  }
$sql = "CREATE DATABASE my_db";
if (mysql_query($sql,$con))
  {
  echo "Database my_db created";
  }
else
  {
  echo "Error creating database: " . mysql_error();
  }
?>

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