Delete repeated fields in a table record)

 

During operation, it was found that a table was not configured with a "primary key". It may be because there was no specification during database design. And the duplicate records appear in it.

First, find the repeated records (first Add a new incremental column ID in this table ):

Select min (ID) as ID from t_table
Group by usercode, reportname
Having count (*)> 1

 

Then you can delete it.

Delete t_table where ID in
(Select Min (ID) as ID from t_table
Group by usercode, reportname
Having count (*)> 1
)

 

You can delete this incremental column and set the column as the primary key.