How to copy data of one vocabulary into another

//copy data of the vocabulary by id=1 into vocabulary id=3
insert into term_data (vid, name, description) select 3, name, description
FROM `term_data` WHERE vid=1;

//update tid data of the new terms.
insert into term_hierarchy (tid) select tid FROM `term_data` WHERE vid=3;

NOTE: don't forget to fix sequences for term_data_tid

May 29, 2018