Using PHP to Run Query on SQL Table

I am working on an internal tool for my team to retrieve data on products based on manufacturer SKU numbers. I tested an idea on my website where you upload a CSV file with a list of SKUs into the MYSQL database using LOAD DATA INFILE through PHP, then output the results into a table using SELECT/JOIN.

The issue with this would be if multiple users upload the CSV at the same time, their results would be combined.

Is there a way to query between a database and CSV file without uploading to the database or a possible way to differentiate each user so their results aren't combined?

Basic elements for the tables would include

CSV File (Currently being imported into a MYSQL table)

Database File

RESULTS

SELECT a.*, b.Description, b.AVG_Price, b.UOM
FROM CSV_Table a
LEFT JOIN Database_Table b
on a.Manufacturer = b.Manufacturer
and a.SKU = b.SKU;