How to Select Specific Rows into a New Table? - sql

Question

I am using SQLite 3. I have a table MyTable, as follows:
Create table mytable (ID as INTEGER, OrderID as INTEGER);
Insert into mytable (ID, OrderID) values (1, 1);
Insert into mytable (ID, OrderID) values (1, 2);
Insert into mytable (ID, OrderID) values (2, 1);
Insert into mytable (ID, OrderID) values (2, 3);
Insert into mytable (ID, OrderID) values (3, 1);
For two rows with same ID but different OrderID, like(1, 1) and (1, 2), we will call them duplicate rows.
Now I need to pick out all duplicate rows and put them into a new table called MyDupTable. For the above sample, MyDupTable should contains:
(1, 1);
(1, 2);
(2, 1);
(2, 3);
So I use the following statement:
Select * into MyDupTable from MyTable group by ID having Count(ID) > 1;
But sqlite gives an error message “near “into”, syntax error”, why?
Thanks

Answer 1

You can do it by using sub-query, sub-query will pick all the duplicate id and then by using in pick rest of the columns from table and insert it in to new table
insert into MyDupTable
select * from mytable where ID in(
select ID from mytable
group by ID
having Count(*) > 1
)
you can create table by using existing table
CREATE TABLE MyDupTable AS
select * from mytable where ID in(
select ID from mytable
group by ID
having Count(*) > 1
)
your query analysis
Select * into MyDupTable from MyTable group by ID having Count(ID) > 1;
1.you have used group by id but not found any selection column from MyTable , number of column used in selection must used in group by
in sql lite insert table docs

Answer 2

I would use INSERT INTO. . . statement with EXISTS :
INSERT INTO MyDupTable (ID, orderid)
SELECT ID, orderid
FROM mytable mt
WHERE EXISTS (SELECT 1 FROM mytable mt1 WHERE mt1.ID = mt.ID AND mt.orderid <> mt1.orderid);
Notes :
Always qualify all columns names when you use INSERT INTO Statement.