There are several identical records in thousands of records. How can I use SQL statements to delete duplicates?
1. Search for redundant duplicate records in the Table. duplicate records are determined based on a single field (peopleid ).
Select * from people
Where peopleid in (select peopleid from people group by peopleid having count (peopleid)> 1)
2. Delete unnecessary duplicate records in the Table. Repeat records are determined based on a single field (eagleid), leaving only the records with the smallest rowid
Delete from people
Where peopleid in (select peopleid from people group by peopleid having count (peopleid)> 1)
And rowid not in (select Min (rowid) from people group by peopleid having count (peopleid)> 1)
3. Search for redundant duplicate records in the table (multiple fields)
Select * From vitae
Where (A. peopleid, A. seq) in (select peopleid, seq from vitae group by peopleid, seq having count (*)> 1)
4. Delete redundant record (multiple fields) in the table, leaving only the records with the smallest rowid
Delete from vitae
Where (A. peopleid, A. seq) in (select peopleid, seq from vitae group by peopleid, seq having count (*)> 1)
And rowid not in (select Min (rowid) from vitae group by peopleid, seq having count (*)> 1)
5. Search for redundant duplicate records (multiple fields) in the table, excluding records with the smallest rowid
Select * From vitae
Where (A. peopleid, A. seq) in (select peopleid, seq from vitae group by peopleid, seq having count (*)> 1)
And rowid not in (select Min (rowid) from vitae group by peopleid, seq having count (*)> 1)
For example, there is a field "name" in Table A, and the "name" values may be the same between different records,
Now, you need to query items with duplicate "name" values between records in the table;
Select name, count (*) from a group by name having count (*)> 1
If the gender is also the same, the statement is as follows:
Select name, sex, count (*) from a group by name, sex having count (*)> 1