Answer Posted / prakash.matte

If we have table 'temp' with columns: id(primary key),
field1, field2, field3, to remove the duplicate (field1,
field2, field3) data we can use either of the below queries

1. delete t1.* from temp t1, temp t2
where t1.id>t2.id and t1.field1=t2.field1 and
t1.field2=t2.field2 and t1.field3=t2.field3;

2. alter ignore table temp ADD UNIQUE INDEX
duprows(field1,field2,field3);

> here we can remove the duprows index by using the
following query:

alter table temp drop index duprows;

we can apply index on the columns as we don't require the
duplicate data, so we don't need to execute the query to
delete the index

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