INSERT INTO table2 (ID, col1, col2, col3, col4)
SELECT
t1.id
, substring_index(t1.col1,';',1)
, substring_index(t1.col1,';',2)
, substring_index(t1.col1,';',3)
, substring_index(t1.col1,';',4)
FROM table1 t1
Voir :http://dev.mysql .com/doc/refman/5.0/en/string-functions.html#function_substring-index