Should I must have a relational CSV to build the relation?

I have build a toy database , with Stock and Industry.
Basically I have 25 Industry and about 8000 Stock. I want to create a link from the stock to industry.

I have a stock.csv with

stock_id, setupDate, name ....

and a stock_industry.csv with

stock_id, name, c_name

Then I first create nodes with Stock by the following:

LOAD CSV WITH HEADERS FROM "file:///stock.csv" AS stock_industry

MERGE (s:Stock { stock_id:stock_industry.stock_id ... })
RETURN count(s)

I then create the the industry nodes with only the industry name.

Then I want to create a "is_industry_of" relationship between the industry nodes and stock nodes:

LOAD CSV WITH HEADERS FROM "file:///stock_industry.csv" AS stock_industry
MATCH (s:Stock),(i:Industry)
WHERE s.stock_code=stock_industry.code AND i.industry=stock_industry.c_name
CREATE (s)-[r:is_industry_of]->(i)
RETURN count(s)

Then I got 0 results.

I searched the Internet, everyone has the third csv file as the relationship between "stock_code, industry_name".

However, I have a csv with the "stock_code, stock_name, industry_name".
Should I just use this csv and avoid using the relation-database-like one?

You've just got this piece the wrong way around. Rather than doing this:

You should do this:

LOAD CSV WITH HEADERS FROM "file:///stock_industry.csv" AS stock_industry
MATCH (s:Stock { id: })
MERGE (i:Industry { name:, c_name: stock_industry.c_name })
MERGE (s)-[:is_industry_of]->(i)
RETURN count(i);

Thanks! Problem perfectly solved!