hi anyone here know how to insert data without overwrite the existing or current data in a table.

i have a table which is store a health information, this health information will change week by week, so i don't want to overwrite information and i want keep as a history info

use a UNIQUE key to prevent duplication

sorry maybe my question a bit confusing, its not INSERT but UPDATE....i want to update a table which is already have a data in the same time i don't want to overwrite the existing data. sorry my english really bad

you want to update, but don't want to overwrite existing data?

that doesn't make sense

please give a specific example of a row that already exists, and the update that you would like to make to it

example:

Table person:

P_Id LastName FirstName Address City
1 John Mayer Street 1 London
2 Ray Caroline Street 2 Leeds

UPDATE Persons
SET Address='Street3', City='Manchester'
WHERE LastName='Ray' AND FirstName='Caroline'

The "Persons" table will now look like this:

P_Id LastName FirstName Address City
1 John Mayer Street 1 London
2 Ray Caroline Street 3 Manchester

but I still want to keep the previous data before the update as a history

aha!!

okay, where would you like to keep it?

obviously not in this table, right?

yup not in this table...do you have any idea, how to insert to new table in the same time update the data in the existing table, probably this is the solution.

an INSERT statement which uses the SELECT option (rather than the VALUES option), followed by an UPDATE statement

Can we not use trigger before insert

trigger before update, i should think