How to insert a record at the end of a table column and not a row?

Question

JavaScript

Hello,
there is a table, for example 3 columns col1, col2, col3.
col1 - line 21
col2 - line 10
col3 - line 30
-------
It is required to add records separately, for example to col2. after some time in col3.
As a result:
col1 - 21 lines
col2 - 11 lines
col3 - 31 lines

Answer 1

https://jsfiddle.net/e813o1cy/1/

Answer 2

SQL operates on strings. Basically, that's the point.
The rest - dancing with insert | update
Well, or as an option for a sparse table:
(row_id, col_id, value), where pk: row_id, col_id