How can rows of one table be represented by columns of another?

Question

MySQL

There is a table Goods

id_good | name
1         good1
2         good2

There is a Warehouses table

id_stage |  name | status
1         stage1      1
2         stage2      1

There is a table GoodsOn the Warehouses (in which warehouses the goods are in the number of pieces)

id_stage | id_good | count
1          1          34
2          2          77

As a result, I need to build a table that will display the quantity of goods in active warehouses

good  | stage1 | stage2
good1    34          0
good2    0            77

Questions:
1. Tell me how to make such a dataprovider for gridview?
The difficulty for me arises precisely in making such a query in which there would be stage1 (and other active stages) as columns.
2. Is it necessary to pass only the dataprovider to the gridview, or is it possible to somehow pass an already formed array?

Answer 1

I'll try to ask you the direction
en.wikipedia.org/wiki/Pivot_table
stackoverflow.com/questions/7674786/mysql-pivot-table

Answer 2

Make a separate model that may not have its own table in the database, make links to the necessary tables in it and use the DataProvider from it.