How to query the database and output the specified field name in thinkphp

When using PHP for website development, querying the database is a very common operation. When using ThinkPHP, an excellent PHP development framework, querying the database is also a very convenient and fast operation. This article will introduce how to use ThinkPHP to query the database and output the specified fields.

1. First you need to connect to the database

In ThinkPHP, connecting to the database is very simple. You only need to configure the corresponding database information in the /config/database.php file.

Taking the mysql database as an example, the configuration file is as follows:

'type'            => 'mysql',         // 数据库类型
'hostname'        => '127.0.0.1',     // 服务器地址
'database'        => 'test_db',       // 数据库名
'username'        => 'test_user',     // 用户名
'password'        => 'test_password', // 密码
'hostport'        => '3306',          // 端口号

2. Building query conditions

Building query conditions is the first step in database query. Generally, you need to use the Query object provided by ThinkPHP to build query conditions. Query object is a chain call method, which can greatly facilitate your query operations.

For example, if you want to query users whose age is greater than or equal to 18 years old in the user table, you can construct the query conditions like this:

use think\db\Query;

$query = new Query();
$query->table('user')
      ->where('age', '>=', 18);
$res = $query->select();

3. Output the specified fields

When performing query operations, only the values ​​of some fields are often required, not the values ​​of all fields. In order to output the specified field, you can add the field method to the query operation and pass in an array. Inside the array are the field names to be queried.

For example, now we need to query the names and ages of all users over 18 years old in the user table. You can do this:

$query->table('user')
      ->where('age', '>=', 18)
      ->field('name, age');
$res = $query->select();

In this way, the query results will only contain the values ​​​​of the two fields of name and age, and the values ​​​​of other fields will not appear in the query results.

4. Summary

The above is how to use ThinkPHP to query the database and output the specified fields. In this way, you can quickly and easily perform database queries and output the query results as the value of the specified field. If you want to learn more about how to use ThinkPHP, you can refer to the official documentation or participate in relevant training courses.

The above is the detailed content of How to query the database and output the specified field name in thinkphp. For more information, please follow other related articles on the PHP Chinese website!