How thinkphp returns certain pieces of data

1. Demand scenarios for returning certain pieces of data

In web development, we often encounter the need to return certain pieces of data. For example, in the "Popular Articles" module of a website, it is necessary to return only the five articles with the highest recent visits; or in the "Sales Ranking" module of an e-commerce website, it is necessary to return only the top ten product information. .

2. Introduction to ThinkPHP query statements

Before learning how to obtain specific data, let us first understand the query statements in ThinkPHP. SQL query statements can be constructed using chain operations (Fluent interface), which is ThinkPHP's approach. The following are some common query operation functions:

1. table(): Specify the table name to be queried

2. field(): Set the table name to be queried Field

3. where(): Set query conditions

4. order(): Set the sorting method of query results

5. limit(): Set the number of query results

6. select(): Perform the query operation and return the result set

3. Return the latest N pieces of data

In many application scenarios, we need to return the latest N pieces of data. This can be achieved through the following ThinkPHP code:

$data = Db::table('my_table')->order('id desc')->limit($N)->select();

The meaning of the above code is to sort the id field in descending order from the my_table table, take out the first N records, and save the result set in the $data array.

4. Return the N pieces of data with the highest number of visits

In website development, many requirements require returning the N pieces of data with the highest number of visits. This can be achieved through the following ThinkPHP code:

$data = Db::table('my_table')->order('views desc')->limit($N)->select();

The meaning of the above code is to sort the views field in descending order from the my_table table, take out the first N records, and save the result set in the $data array.

5. Return the TOP N values ​​of a certain field

In many cases, we need to get the top N values ​​of a certain column, such as the top ten sales product information. This can be achieved through the following ThinkPHP code:

$data = Db::table('my_table')->field('id, name, sales')->order('sales desc')->limit($N)->select();

The meaning of the above code is to select the three fields of id, name, and sales from the my_table table, sort them in descending order according to the sales field, take out the first N records, and put the results The set is stored in the $data array.

6. Return data within the specified range

Occasionally we need to call data within a specific range, such as querying user information with IDs between 100 and 200 . This can be achieved through the following ThinkPHP code:

$data = Db::table('my_table')->where('id', 'between', [100, 200])->select();

The meaning of the above code is to select all records with ids between 100 and 200 from the my_table table and save the result set in the $data array.

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