I have a table with 3 col and 4 row.
Col1 Col2 Col3
Row1 A1 B1 1
Row2 A2 B2 0
Row3 A3 B3 3
Row4 A4 B4 1
A select * from [table] returns:
A1 B1 1
A2 B2 0
A3 B3 3
A4 B4 1
I Want a select that give:
A1 B1 1
A3 B3 3
A3 B3 3
A3 B3 3
A4 B4 1
Col3 gives the number of row return.
Start with a numbers table... a table with one row for each number, going up as high as the largest possible value in your Col3. It will look something like this:
Table: Numbers
Value
-----
1
2
3
4
5
...
Then you you can JOIN to this table using an inequality:
SELECT Col1, Col2, Col3
FROM [table] t
INNER JOIN NUMBERS n ON n.Value <= t.Col3
This will make your Row3 value match to the Numbers table 3 times, duplicating that row in the results, whereas the Row2 value won't match any records from the Numbers table, removing it from the results.
There are several options for generating a Numbers table you can look at here:
What is the best way to create and populate a numbers table?
With the Option 6 from that question:
WITH Numbers AS (
SELECT TOP 10000 row_number() over(order by t1.number) as [Value]
FROM master..spt_values t1
CROSS JOIN master..spt_values t2
)
SELECT Col1, Col2, Col3
FROM [table] t
INNER JOIN NUMBERS n ON n.Value <= t.Col3
Note that this is overkill for your sample data, which only goes to 3. For anything less than about 50, you could just hard-code the table. I'm assuming your real data goes much higher.
Related
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
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.
I have two tables with one to many relationship. I want to write a query which outputs all records from table with one record and only one record from the table having many records.
So the table having many records with first show the most occurring record. If there are equal occurrences then it will Order by ascending and show the first record.
Table1
Col1 Col2 Col3
a1 1 4
a2 2 5
a3 3 6
Table2
Col1 Col4
a1 10
a1 11
a1 22
a1 11
a2 10
a2 11
a3 19
a3 22
a3 22
a3 23
Query output:
Col1 Col2 Col3 Col4
a1 1 4 11
a2 2 5 10
a3 3 6 22
Hope I made it clear.
First you need to use a group by along with a min() to get the smallest number from table2, then you join to table1 to get the columns you need. I've used a left join as I'm assuming there may not be a match in table2 but you can change it to an INNER JOIN if there are always 1 or more corresponding records in table2.
SELECT a.col1, a.col2, a.col3, b.col4
FROM table1 a
LEFT JOIN (
SELECT col1, col4 = MIN(col4)
FROM table2
GROUP BY col1
) b
ON a.col1 = b.col1
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