Retrieve data by comparing date column from multiple tables

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MySQL

I have 4 tables with foreign key in each tables to join and a date column(last updated date).
I want to get the recent updated date by comparing dates column from the 4 tables.

table#1 - pk_id | last_added

table#2 - pk_id | fk_id | last_updated_table2

table#3 - pk_id | fk_id | last_updated_table3

table#4 - pk_id | fk_id | last_updated_table4


Here i want to sort records(pk_id of table#1) by comparing all the date column of 4 tables.