A brief analysis of the inclusion query function of php database

In the process of developing web applications, database query is a very important link. It is quite common to use database queries in PHP development, which can help us obtain data easily.

When performing database queries, sometimes we need to find records that contain a certain field. In this case, we need to use include queries.

Inclusion queries are used to find records that contain a certain string or value. In php, we can use the LIKE operator to perform include queries. This operator is often called fuzzy query.

The following is an example containing a query:

SELECT * FROM table_name WHERE column_name LIKE '%search_string%';

In this example, table_name is the table name to be queried, column_name is the column name to be queried, and search_string is the string to be searched.

The LIKE operator is used to match any part of the search_string. % is a wildcard character that represents any character or any number of characters.

For example, if we want to find records that contain the string "php", we can use the following query:

SELECT * FROM table_name WHERE column_name LIKE '%php%';

This will return all records that contain the string "php".

In addition to the % wildcard character, we can also use the _ wildcard character to match a single character. For example, if we want to find all words starting with "p" and ending with "t", we can use the following query:

SELECT * FROM table_name WHERE column_name LIKE 'p_t';

This will return words like "part", "post", "plot" and other words.

It should be noted that when performing include queries, performance factors need to be taken into consideration. Because the LIKE operator scans every row in the table, it can be very slow when used with large tables.

Therefore, we recommend that when using include queries, only query necessary columns and use indexes to improve query performance.

In summary, containment query is a very useful tool that can help us quickly find records containing specific strings. When using it, you need to consider performance issues and use indexes and appropriate query statements to optimize performance.

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