How to use php mysql_query()

php mysql_query() function is used to execute sql statements. When querying, updating, and adding data, you can write the sql statement, and then use the mysql_query() function to execute the sql statement to operate the specified database; syntax " mysql_query($sql [,$con])".

The operating environment of this tutorial: windows7 system, PHP5 version, DELL G3 computer

php mysql_query function is used to execute sql statements, such as in queries When updating or adding data, we generally write the sql statement and then use mysql_query to perform the operations required by sql.

Let’s look at an example first:

<?php
  $host="mysql153.secureserver.net";
  $uname="root";
  $pass="password";
  $database="manongjc";
  
  $connection= mysql_connect ($host, $uname, $pass) or die ("Database connection failed!");
  $result=mysql_select_db ($database) or die ("Database could not be selected");
  $query = "drop table if exists mytable";
  $result = mysql_query ($query) or die ("Query failed.");
?>

The steps for php to operate the database can be roughly divided into the following steps:

• 1. Connect to the database server

• 2. Select the database to be operated

• 3. Execute the SQL statement

• 4. The result set obtained by processing the SQL statement

• 5. Close or disconnect the database server

The third step is required to execute the sql statement. mysql_query() function, as shown in the above example:

  $query = "drop table if exists mytable";
  $result = mysql_query ($query)

This SQL statement is the command to delete the table mytable. If the execution is successful, it returns true, otherwise it returns false. But the mysql_query function does not necessarily return only true and false.

The mysql_query function returns a resource identifier for a SELECT, SHOW, EXPLAIN, or DESCRIBE statement, or FALSE if the query is executed incorrectly. For other types of SQL statements, mysql_query() returns TRUE on success and FALSE on error.

Note:

mysql_query() is deprecated as of PHP 5.5.0 and will be removed as of PHP 7.0.0. It should be replaced with the MySQLi or PDO_MySQL extension. Alternatives to this function are:

• mysqli_query()

• PDO::query()

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