Hi Alex,
Thank you for your interest in wpdatatables.

MySQL is a powerful, yet free, SQL-based database engine. It allows you to create both small and very large databases, and to create, read, and edit data in these databases quickly and effectively. That’s why it has been the #1 database engine on the web for many years. Even WordPress runs on MySQL.

wpDataTables is deeply integrated with the MySQL engine. It allows you to display results of SQL query in a table, you can use MySQL server to do searches/filters/sorting/pagination for large datasets, it allows front-end (and back-end) editing of MySQL tables, creating MySQL tables from back-end, importing CSV or Excel to editable MySQL tables, generating SQL queries with visual constructor, and much more.

Yes you can use queries that will make pivot tables like this (https://stackoverflow.com/questions/13944417/mysql-convert-column-to-row-pivot-table)

When you made table like this you will have to prepare a MySQL view (a stored query), which will return the data that you need, call it e.g. “view1” and then build a wpDataTabled based on a simple query like “SELECT * FROM view1″, because there is a chance that wpDataTable doesn’t work correctly with server-side processing, probably this is happening because wpDataTables server has problems with parsing of the query and building new queries dynamically (rarely happens, but does sometimes). 

Please note: Using this plugin feature requires at least a basic knowledge of SQL. It is assumed that you can create the table in some MySQL data manager (e.g., PHPMyAdmin, MySQL Workbench), and prepare a SQL query that will return the data you need. If you do not know how to use MySQL, refer to the “Create a MySQL-query-based table by generating a query to MySQL database” section. It will explain how to create complete tables or MySQL queries without this basic knowledge. Please be advised that preparing MySQL queries for you is not included in the plugin support, but it can be done as a paid customization service.

Unfortunately at the moment it is not possible to import excel file on already made wpdatatables.

In many cases, you might have an initial file with the table data, but this table needs to be regularly updated (e.g. if it is a price list, a catalog, etc.). wpDataTables has two options here for you:

1.  Creating tables linked to existing data source, in which case you will upload the file and initialize the table, whereupon it will be read every time on page load. Then you can overwrite this file to update the data. Such tables won’t be editable within WordPress, and if they are larger than 3000-5000 rows, the page load and generation time will be slow.
2. Importing table data to WordPress. The initial data will be read and imported from the provided file (Excel, CSV or Google Spreadsheet). You can select to skip certain columns, or add columns. You can edit both the structure and the data within the table at an any point later, but the table won’t be synced with the source file as is the case with the first option but will be editable; e.g., if you change something in CSV, Excel or in source Google Spreadsheet, your wpDataTable data will stay the same because the data will be already imported to the database.

You can try our sandbox site: Front-end & Back-end - you can find a fully functional version there to try out all plugin features.

Sorry for being so detail, but we want to make sure that we explained you are or aren't your needs possible with  our plugin.

Best regard.