Sql – Insert value in first empty cell of column and show ID - php

Question

I have an sql statement that will insert a value to the first empty cell. And if I ran the php script again, then it inserts into the next null cell etc.
Problem: I also want to find out the ID of that row, and value of another column in that row. In the Mysql table below, I want a value inserted in the first ‘null’ of COLUMN A, and also know the id and value in COLUMN B corresponding to that (ie id=3 and COLUMN B= 11).
My_TABLE
+---------+--------------+-------------+
| ID | COLUMN A | COLUMN B |
+---------+--------------+-------------+
| 1 | 6 | 78 |
| 2 | 7 | 90 |
| 3 | NULL | 11 |
| 4 | NULL | 5 |
| 5 | NULL | 123 |
+---------+--------------+-------------+
The following sql statement in PHP script will make it possible to insert value to the first empty cell in COLUMN A:
UPDATE My_TABLE
SET COLUMN A = 83
WHERE COLUMN A IS NULL
LIMIT 1;
Result will be:
+----+----------+------------+
| ID | COLUMN A | COLUMN B |
+----+----------+------------+
| 1 | 6 | 78 |
| 2 | 7 | 90 |
| 3 | 83 | 11 |
| 4 | NULL | 5 |
| 5 | NULL | 123 |
+----+----------+------------+
I also want to have an sql script that will print within PHP (echo) the values of ID and COLUMN B values corresponding to the first COLUMN A null value (ie ID= 3; COLUMN B= 11).

Answer 1

fetch the row by condition in this case you will have ID and COLUMN B
select *
from My_TABLE
where COLUMN A IS NULL
order by id
limit 1
Update by ID the selected row:
update My_TABLE
set COLUMN A = :SOME_VALUE
where ID = :ID_FROM_FETCH

Answer 2

Not sure if this case will fit what you are questioning.
mysqli_insert_id
From this function I'm pretty sure you will able to write the script for what you need.
Note* If it fits what you need, please read the warning as I'm not
sure if it will deprecated from the latest PHP version. Kindly take
note.