Could you please help me in deleting duplicates (partial) from table? I have a table containing 5 columns. And in this table I have duplicates -- but only 4 columns are the same and one of the columns (field5) is different. That is:
F1 F2 F3 F4 F5
A1 A2 A3 A4 103
A1 A2 A3 A4 3
So, for a duplicate, 4 columns/fields are the same, except the 5th one. And I want to delete the row containing number "103", that's, a higher number. How can I achieve this?
If this was a normal duplicate, I would just use max(rowid) and remove that row. But now this could delete the row containing lower number instead of the higher number.
One method that I can think of is creating a new table containing rows which are duplicate and Field5 has a higher number from this table. Then deleting rows from original table by comparing it to this new table. But that seems not so good solution to me -- especially if the original table is big, this might take long time.
Any help would be much appreciated. Thank you.
Idea is to keep a record for each combinations of F1,F2,F3,F4 and delete the rest.
Try this:
DELETE FROM TABLE_NAME WHERE ROWID IN
(SELECT ROWID FROM
(SELECT ROWID, row_number() OVER(PARTITION BY F1,F2,F3,F4 ORDER BY F5) RN
FROM TABLE_NAME)
WHERE RN<>1);
How about this?
SQL> select * from test order by f1, f5;
F1 F2 F3 F4 F5
-- -- -- -- ----------
a1 a2 a3 a4 3
a1 a2 a3 a4 50 --> delete
a1 a2 a3 a4 103 --> delete
b1 b2 b3 b4 2
b1 b2 b3 b4 200 --> delete
c1 c2 c3 c4 1
6 rows selected.
SQL> delete from test t
2 where rowid not in (select rowid
3 from test t1
4 where t1.f1 = t.f1
5 and t1.f2 = t.f2
6 and t1.f3 = t.f3
7 and t1.f4 = t.f4
8 and t1.f5 =
9 (select min (t2.f5)
10 from test t2
11 where t2.f1 = t.f1
12 and t2.f2 = t.f2
13 and t2.f3 = t.f3
14 and t2.f4 = t.f4));
3 rows deleted.
SQL> select * from test order by f1, f5;
F1 F2 F3 F4 F5
-- -- -- -- ----------
a1 a2 a3 a4 3
b1 b2 b3 b4 2
c1 c2 c3 c4 1
SQL>
I normally just do this:
delete demo
where rowid in
( select lead(rowid) over (partition by f1, f2, f3, f4 order by f5) as next_rowid
from demo );
That is, delete every "next" row in order of f5 within its (f1, f2, f3, f4) group.
Related
I have an in-memory table as follows:
A1 B1 C1
A2 B2 C2
A3 B3 C3
How can I turn it into the table below?
A3 B3 C3
A2 B2 C2
A1 B1 C1
I have tried by adding an auto-increment field. Use keyword order by and desc to sort the records based on the new column on descending order. Then, I get the expected result after deleting this column. I wonder if there is a more convenient way to get a reversed table.
You can use the rowNo function to sort columns without adding a new auto-increment field.
t=table(`A1`A2`A3 as col1,`B1`B2`B3 as col2,`C1`C2`C3 as col3)
select * from t order by rowNo(col1) desc
Output:
col1 col2 col3
---- ---- ----
A3 B3 C3
A2 B2 C2
A1 B1 C1
I have a table with sample values as below
In this table, all the values in Col1 will have its supporting values in Col2. The values A1 and A2 are like master values and they will never appear in Col2. I need to make an output displaying this master values in a new column like below
What would be the best way to achieve this in Oracle SQL?
Looks like a hierarchical query:
SQL> select connect_by_root t.col1 as main,
2 t.col1,
3 t.col2
4 from test t
5 start with t.col1 in ('A1', 'A2')
6 connect by t.col1 = prior t.col2
7 order by main, t.col1, t.col2;
MAIN COL1 COL2
----- ----- -----
A1 A1 B1
A1 A1 B2
A1 A1 B3
A1 B1 C1
A1 B2 C2
A1 C1 D1
A2 A2 E1
A2 A2 E2
A2 E1 F1
A2 E1 F2
10 rows selected.
SQL>
Need help with Oracle query which will provide the output in below the format.
Sample table
c1 c2 c3 c4
-- -- -- --
A 1 A1
B 2 B1 C1
D 6 E2 A1
A 2 A1
C 3 C1
D 4 D1 E1
I want to join same table where data in 3rd Column matches the data in 4th and expecting the data to be sorted as subsequent records as below
c1 c2 c3 c4
-- -- -- --
A 1 A1
A 2 A1
D 6 E2 A1
B 2 B1 C1
C 3 C1
That's not a grouping, it's a sorting that you need:
select *
from your_table
order by coalesce(col1,'ZZZ') desc,
col2 desc --coalesce will use 'ZZZ' to order if column is null
Initial Situation:
Table1:
Table1 s1_a s2_b s3_c s_key
Table1 a1 b1 c1 1
Table1 a2 b2 c2 2
Table1 a3 b3 c3 3
Table1 a4 b4 c4 4
Table2:
Table2 d1_q d2_w d3_e d_key
Table2 q1 w1 e1 1
Table2 q2 w2 e2 2
Table2 q3 w3 e3 3
How can I get this result: common columns are s_key & d_key -> key
Extract View s1_a s2_b s3_c key d1_q d2_w d3_e
Extract View a1 b1 c1 1
Extract View a2 b2 c2 2
Extract View a3 b3 c3 3
Extract View a4 b4 c4 4
Extract View 1 q1 w1 e1
Extract View 2 q2 w2 e2
Extract View 3 q3 w3 e3
No reason for a cross join here. Just an old fashioned UNION ALL will do the trick:
SELECT s1_a, s2_b, s3_c, s_key, NULL as d1_q, NULL as d2_w, NULL as d3_e FROM Table1
UNION ALL
SELECT NULL, NULL, NULL, d_key, d1_q, d2_w, d3_e FROM Table2
Below is the sample data:
c1 c2 c3 c4 c5
1 a1 a 1 1
2 a2 a 2 1
3 a3 a 3 1
4 a4 a 4 1
5 b1 b 1 1
6 b2 b 2 1
7 b3 b 3 1
8 b4 b 4 1
9 a1 c 3 1
I want to get the the below details:
c1 c2 c3 c4 c5
1 a1 a 1 1
5 b1 b 1 1
9 a1 c 3 1
C1 is primary key, the criteria is for any given unique(c2) where c4 is the lowest, I want to return the contents(all the 5 columns) of the row.
Try this:
SELECT t1.*
FROM Table1 t1
INNER JOIN
(
SELECT c3, MIN(c4) c4
FROM Table1
GROUP BY c3
) t2 ON t1.c3 = t2.c3 ANd t1.c4 = t2.c4
SQL Fiddle Demo
Update:1 In SQL the returned results is a set set(unless you specify an ORDER BY clause, it is a cursor in this case), wherein the order is not guaranteed. This is a standard. You should use an ORDER BY clause if you want to guarantee a specific order. In your case , the results is not guaranteed to be ordered like 1 5 9. Add ORDER BY c1 instead.
The ORDER BY clause might be crucial in some cases, for example, if want to get the top three rows, or the maximum one, in this case you have to specify an ORDER BY clause.
So if you wants to persist a specific order the you have specify an ORDER BY.
1 As noted by #Fahim Parker, see the comments below.
select c1,c2,c3,c4,c5
from table
where c4= (select min(c4) from table as f where f.c4 = table.c4);
i hope that helps