SELECT * FROM tbl WHERE col_1 LIKE '%'+col_2+'%'
EDIT:För MySQL skulle motsvarande syntax vara:
SELECT * FROM tbl WHERE col_1 LIKE CONCAT('%',col_2,'%')
SELECT * FROM tbl WHERE col_1 LIKE '%'+col_2+'%'
EDIT:För MySQL skulle motsvarande syntax vara:
SELECT * FROM tbl WHERE col_1 LIKE CONCAT('%',col_2,'%')