Swap column values across 2 different tables - mysql

Question

I have two tables and need to swap the values of a column in each table - I can do this when they are in the same table but when I try to do this with different tables then the second value is already overwritten so gets lost.
For example:
table1
id user_id currency col2 col3......
1 1 10 Bob 2018-04-16
2 2 150 Tom 2018-05-17
3 3 60 Phil 2018-06-04
4 4 125 Jon 2017-12-01
5 5 35 Mike 2018-07-21
table2
id user_id salary col2 col3......
1 1 USD 16 Active
2 2 USD 17 Active
3 3 GBP 21 Left
4 4 CAD 16 Active
5 5 AUD 19 Active
I need these to look like:
table1
id user_id currency col2 col3......
1 1 USD Bob 2018-04-16
2 2 USD Tom 2018-05-17
3 3 GBP Phil 2018-06-04
4 4 CAD Jon 2017-12-01
5 5 AUD Mike 2018-07-21
table2
id user_id salary col2 col3......
1 1 10 16 Active
2 2 150 17 Active
3 3 60 21 Left
4 4 125 16 Active
5 5 35 19 Active
I tried:
UPDATE table1 t1, table2 t2
SET t1.currency=t2.salary, t2.salary=t1.currency
WHERE t1.user_id=t2.user_id;
but this does not work (currency gets set correctly but not the salary), is it possible to do?
Swap two columns values between two tables looked like a possible solution but the solution is changing table names as all the columns need swopped whereas I only need single columns swapped.

Answer 1

I believe you'll need to use a mix of both DDL and DML to do this.
First off you'll need to rename one of the columns to be swapped and add a column to hold the new value:
alter table table1 change currency salary int;
alter table table1 add currency varchar(3) after salary;
then update each table independently:
update table1 t1, table2 t2
set t1.currency = t2.salary
where t1.user_id = t2.user_id;
update table1 t1, table2 t2
set t2.salary = t1.salary
where t1.user_id = t2.user_id;
and finally remove the extra column:
alter table table1 drop salary;