I'd like to change

{foo, {bar}, foobar}

to

{foo, bar, foobar}

in all rows that match '{.*{'. I.e. remove all curly braces { and } except the outer most pair.

So doing

mysql -h $H -u $U -p$P $DB -B -e "SELECT id FROM t WHERE col REGEXP '{.*{'" > bad.txt

selects all the rows that will need this substitution. How do I make this substitution very quickly?

EDIT:

Could I do it by

update table set column = REPLACE(column,'{','');

Then restore the out most pair

update table set column = REPLACE(column,'^','{');

update table set column = REPLACE(column,'$','}');