How to do this table update

[ecabanas]

     Hi guys,

I want to do a table that reflects all the changes from items table. Every Item can change the status every day and I want to do a "log Table"  and record the changes in a table and have all history.

Every night I want to update (add the new changes) the table.

INVENTTABLE

Itemid       Date        Status

a               1/1/15       on

b               1/1/15       on

c               1/1/15       off

d               1/1/15       on

ITEM_LOG

Itemid       Date        Status

a               1/1/15       on

b               1/1/15       on

c               1/1/15       off

d               1/1/15       on

DAY 2 change some items

INVENTTABLE

Itemid       Date        Status

a               2/1/15       on

b               2/1/15       off

c               2/1/15       on

d               2/1/15       on

ITEM_LOG

Itemid       Date        Status

a               1/1/15       on

b               1/1/15       on

c               1/1/15       off

d               1/1/15       on

b               2/1/15       off

c               2/1/15       on

Many thank's

Eduard