Question

Example of my table:

Table_1

+-----id-----+-----zone-----+-----address-----+-----status-----+
=============+==============+=================+================+
     1              5                10               ok
     2              2                 8               ok
     3              3                 2               ok  
     4              2                 5               ok
     5              3                 2               ok 
     6              5                10               ok     
     7              3                 2               ok    

I need to check the duplicate entries [zone/address combination] and have the table like this:

Table_1

+-----id-----+-----zone-----+-----address-----+-----status-----+
=============+==============+=================+================+
     1              5                10               ok
     2              2                 8               ok
     3              3                 2               ok  
     4              2                 5               ok
     5              3                 2               duplicate 
     6              5                10               duplicate 
     7              3                 2               duplicate 

The query should check the duplicate combination of zone, address and should update the ‘status’ column.
I need to keep the first duplicate data status unchanged and the rest of the repeated data should be marked as ‘duplicate’?

Any ideas on how to do this?

Answer 1

You could use this:

update
  Table_1 t1 inner join Table_1 t2
  on t1.zone=t2.zone
     and t1.address=t2.address
     and t1.id>t2.id
set t1.status='duplicate'