Postgres 10

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create table customer as 
select * FROM ( VALUES ('e''QmfgLu/]sf]/sd' :: text), ('foo''''bar') ) as s(name);

SELECT 2

select * from customer;

name

e'QmfgLu/]sf]/sd

foo''bar

SELECT 2

update customer set name=REGEXP_REPLACE(name, $$([^'])'([^'])$$, $$\1''\2$$ ,'g');

UPDATE 2

select * from customer;

name

e''QmfgLu/]sf]/sd

foo''bar

SELECT 2