What is the principle behind MySQL’s pagination queries?

The principle of MySQL pagination query is achieved through the use of LIMIT and OFFSET.

LIMIT is used to restrict the number of rows returned in a query, while OFFSET is used to specify the starting position of the query results. When performing pagination queries with LIMIT and OFFSET, it is usually necessary to include an ORDER BY clause to specify the sorting criteria of the query results.

The specific steps for paging query are as follows:

1. First, execute a query without LIMIT and OFFSET to retrieve the total number of rows that meet the conditions (for example: SELECT COUNT(*) FROM table_name WHERE conditions).
2. Calculate the OFFSET value based on the number of rows displayed per page and the current page number (e.g. OFFSET = (current page number – 1) * number of rows displayed per page).
3. Execute a query statement with LIMIT and OFFSET to retrieve data from the current page (e.g. : SELECT * FROM table_name WHERE conditions ORDER BY column_name LIMIT number of rows per page OFFSET offset value).

By using this method, the pagination feature of MySQL can be achieved.