将id的值赋给insert查询中的任何列

Description :

I have an insert query that inserts data perfectly..

Now to keep track of record I have a product_id which is same as the id of the table which is auto increment

the method I am using is I get the last id in the table , increment it and assign the value to product_id.. It works perfectly but there is a bug in my code and that is when the table is empty there is no last id to fetch and increment ...

So by default it gets 0 , increments it to 1 and assigns the value to product id ...

this starts to work perfectly when the query is run again because the second time there actually is last id to fetch

So table looks something like this

what I want is

id | post_id

231 | 1

232 | 232

what I want is

id | post_id

231 | 231

232 | 232

So is there any way that I upon inserting the data could assign the value of id to product_id so they both are equal as if there were two auto increments ... Anyone ??