Database Table1 Update Table 2 Problems!

[tpiano]

your table doesnt need to be in order. it will do a one to one match base on how you order it on your insert select statement.

what the where clause do is insert all those records from table2 to table1 for all same product_id.

if you use product_id as your primary key in table1 without duplicates, then you'll encounter a primary key constraints.. do the necessary trapping.