Load an .xlsx file into mysql table or convert it to .csv in PHP

I have an excel file (.xlsx) with 2 columns (date, number).
I have a mysql table with 2 columns (date, number) where number is decimal.

I am trying to load this file into my table in mysql.

The first column (date) is in a date format : %d/%m/%Y but I want it to be : %Y-%m-%d.

The second column is in an Accounting format.

I am using the following code :

$Db->query('LOAD DATA LOCAL INFILE \'/file.xlsx\'  
        INTO TABLE '.$in_table.'
        FIELDS TERMINATED BY \',\'
        ENCLOSED BY \'"\'
        LINES TERMINATED BY \'\n\'
        IGNORE 8 ROWS
        (@date, number)
        set date=str_to_date(@date,\'%Y-%m-%d\')
        ;'); 

01) It does not upload the dates because of my set. How can I upload them in the right format and convert it in the load query without using update?

02) It does not upload the number cells.

03) Additionally, I want to use this code :

$Db->query('delete from '.$in_table.' 
        where date is null or number = 0
        ;');

in order to delete the rows that do not start with a date format and also the rows where the number is empty. Here is the excel file in a printscreen :

So, according to (03), rows 32,33 and 34 should not be included in my sql table.

I want to load or either convert the .xlsx to .csv if I have to. I want to do it either in php or sql code (in a php file). I tried many versions but they are all wrong.