The semi-colon needs to be inside the last double quote with a closing param. When adding single quotes around a string, remember to add them outside your selected cell.
(spaces added for visibility – remove before inserting)
=CONCATENATE("insert into table (id, name) values (",C2,",' ",D2," ');")
Here is another view:
=CONCATENATE(“insert into table (id, date, price) values (“,C3,”,'”,D3,”‘,”,B3,”);”)