Q:

MariaDB shows no results when I use INNER JOIN

There are two tables. The IDs of Table B was created by Table A. ID. So, the IDs of both tables are identical. 
This is my question and real table structures.
I have tried to merge two tables into one table, but the query shows no result. 
This is my query. 
SELECT A.ID, A.type, B.ID, B.result 
FROM A
INNER JOIN B
ON A.ID = B.ID;

I don't know what I did wrong. I thought it is quite simple JOIN syntax. 
Can you explain what I did wrong? 

A:

Dear titans of the stack overflow.
I've solved this problem. 
I had tried to join the two tables using admno column. 
It looked same, and the data types are same. but After checking the length of that data, I found out that there is something, an invisible byte in one column.
(The trim() function was not able to remove that byte) 
I used char_length() function at each key column. It revealed that one is 14, and another is 15. 
I don't know what is the invisible. But it worked!
Thank you all!

