查询花时间执行

I have a query that fetches data from two tables but it takes too much time to fetch data. The browser loads and shows nothing as a result. When I run this query in the MySQL database, it takes a long time to execute.

SELECT 
    * 
FROM 
    library_new_item AS library 
    LEFT JOIN library_items_barcode AS boorcode ON library.lib_item_id=boorcode.lib_items_id 
ORDER BY 
    library.lib_item_id ASC 
LIMIT 100

Unless you post your DB structure, or share the Explain output or the error message, it'd be impossible for us to answer. But if you want us to take a shot in the dark, this could possibly be the issue:

on library.lib_item_id = boorcode.lib_items_id