mysql - Update in the same table with an inner join -

my actual (and broken) query this:

update t_1 set b=(select b t_1 a=1)  b=1

how can using inner join?

you can cheat mysql on this:

update t_1  set b=(select b (select * t_1) t a=1)   b=1

a join version:

update t_1 join (select * t_1) t on t.a = 1 , t_1.b=1 set t_1.b= t.b;

where source proving sub queries slower joins?

Macro