I have a problem with PL/SQL since i am new in PL/SQL world.
Let's say i have table like this.
COlumnA COlumnB COlumnC
1 5000000000 X
1 5000000000 X
2 4350000000 X
2 4350000000 X
3 10000000000 X
3 10000000000 X
3 10000000000 X
4 1809469720 Y
5 10000000000 X
5 10000000000 X
6 3000000000 X
6 3000000000 X
And i want to produce select statement as below.
ColumnC |Sum
X |32350000000
Y |1809469720
I have solved this problem in Oracle 12c with inner query, but when the system need to go to Oracle 11g, my query doesn't work anymore, i need to have the expected result with only one select statement.
Could anyone please advise?
Thank you!
This is what I came up with... using an inline view rather than a correlated subquery in the SELECT list.
SELECT d.columnc AS "ColumnC"
, SUM(d.columnb) AS "Sum"
FROM ( SELECT t.columna
, t.columnb
, t.columnc
FROM tablea t
GROUP
BY t.columna
, t.columnb
, t.columnc
) d
GROUP
BY d.columnc
This uses an inline view (aliased as "d") to return a "distinct" set of rows from tablea. We can get a distinct set, using a GROUP BY clause, or including the DISTINCT keyword, or even by writing a query that uses a UNION set operator.
Just wrap that query in parens, assign an alias, and use it in the FROM clause, as if it were a table or view.
The statement operates similarly to referencing a VIEW in the FROM clause.
You don't need to do this, but to illustrate how the query above operates. We could create a view, like this:
CREATE VIEW d AS
SELECT t.columna
, t.columnb
, t.columnc
FROM tablea t
GROUP
BY t.columna
, t.columnb
, t.columnc
And then we can reference the view in the FROM clause of another query, for example
SELECT d.columnc AS "ColumnC"
, SUM(d.columnb) AS "Sum"
FROM d
GROUP
BY d.columnc
But we don't actually need to create the VIEW object. We can include the view query as an "inline view".
I don't believe that Oracle 11g has a restriction on the nesting of inline views to three levels. I suspect that the restriction you are running into is related to correlated subqueries. The subquery can reference columns from the outer query, but only up one level... columns from the query it's used in. It can't reference columns in a query that is further out. (I've not confirmed with testing, but that's my recollection.)
This is where the actual ORA- and/or PLS- error message from Oracle would be of some help in identifying the restriction you are running into.
First find the distinct values of COlumnA,COlumnB and COlumnC then do the aggregation
Try this
select COlumnC,sum(COlumnB) from
(
select distinct COlumnA,COlumnB,COlumnC
from Table1
)
Group by COlumnC
Or you can simple use this query.
Select sum(columnB) as sum,columnC from table_name group by ColumnC;
Related
hi i have 3 questions on sql please :
1-about this simple code
1. with cte as (
2. select * from TABLE1)
3. select * from cte
when select * from TABLE1 compute?
first the line 3 call and then line 1 then line 2
or first 1+2 and then 3?
2- when i do left/right join i have got some row with null, that make sense .
but how can i insert to the row will null "0" instead null?
to all of the row that because the left/right join get null ( if i use inner join i will not show this row )
thanks!
The order of execution is up to the database. The order of execution will depend on tables statistics and other factors. I've seen both order of execution.
If you have a NULL value and you want to show zero, use NVL for Oracle, e.g. NVL(myColumn,0) this will return myColumn if it's not null, otherwise 0. ISNULL for SQL Server and MySQL.
I have searched a lot, but most of solutions are for concatenation option and not what I really want.
I have a table called X (in a Postgres database):
anm_id anm_category anm_sales
1 a_dog 100
2 b_dog 50
3 c_dog 60
4 a_cat 70
5 b_cat 80
6 c_cat 40
I want to get total sales by grouping 'a_dog', 'b_dog', 'c_dog' as dogs and 'a_cat', 'b_cat', 'c_cat' as cats.
I cannot change the data in the table as it is an external data base from which I am supposed to get information only.
How to do this using an SQL query? It does not need to be specific to Postgres.
Use case statement to group the animals of same categories together
SELECT CASE
WHEN anm_category LIKE '%dog' THEN 'Dogs'
WHEN anm_category LIKE '%cat' THEN 'cats'
ELSE 'Others'
END AS Animals_category,
Sum(anm_sales) AS total_sales
FROM yourtables
GROUP BY CASE
WHEN anm_category LIKE '%dog' THEN 'Dogs'
WHEN anm_category LIKE '%cat' THEN 'cats'
ELSE 'Others'
END
Also this query should work with most of the databases.
By using PostgreSQL's split_part()
select animal||'s' animal_cat,count(*) total_sales,sum(anm_sales) sales_sum from(
select split_part(anm_cat,'_',2) animal,anm_sales from x
)t
group by animal
sqlfiddle
By creating split_str() in MySQL
select animal||'s' animal_cat,count(*) total_sales,sum(anm_sales) sales_sum from(
select split_str(anm_cat,'_',2) animal,anm_sales from x
)t
group by animal
sqlfiddle
You could group by a substr of anm_catogery:
SELECT SUBSTR(anm_catogery, 3) || 's', COUNT(*)
FROM x
GROUP BY anm_catogery
If you have a constant length of the appendix like in the example:
SELECT CASE right(anm_category, 3) AS animal_type -- 3 last char
, sum(anm_sales) AS total_sales
FROM x
GROUP BY 1;
You don't need a CASE statement at all, but if you use one, make it a "simple" CASE:
Simplify nested case when statement
Use a positional reference instead of repeating a possibly lengthy expression.
If the length varies, but there is always a single underscore like in the example:
SELECT split_part(anm_category, '_', 2) AS animal_type -- word after "_"
, sum(anm_sales) AS total_sales
FROM x
GROUP BY 1;
Hi how can I get the percentage of each record over the total?
Lets imagine I have one table with the following
ID code Points
1 101 2
2 201 3
3 233 4
4 123 1
The percentage for ID 1 is 20% for 2 is 30% and so one
how do I get it?
There's a couple approaches to getting that result.
You essentially need the "total" points from the whole table (or whatever subset), and get that repeated on each row. Getting the percentage is a simple matter of arithmetic, the expression you use for that depends on the datatypes, and how you want that formatted.
Here's one way (out a couple possible ways) to get the specified result:
SELECT t.id
, t.code
, t.points
-- , s.tot_points
, ROUND(t.points * 100.0 / s.tot_points,1) AS percentage
FROM onetable t
CROSS
JOIN ( SELECT SUM(r.points) AS tot_points
FROM onetable r
) s
ORDER BY t.id
The view query s is run first, that gives a single row. The join operation matches that row with every row from t. And that gives us the values we need to calculate a percentage.
Another way to get this result, without using a join operation, is to use a subquery in the SELECT list to return the total.
Note that the join approach can be extended to get percentage for each "group" of records.
id type points %type
-- ---- ------ -----
1 sold 11 22%
2 sold 4 8%
3 sold 25 50%
4 bought 1 50%
5 bought 1 50%
6 sold 10 20%
To get that result, we can use the same query, but a a view query for s that returns total GROUP BY r.type, and then the join operation isn't a CROSS join, but a match based on type:
SELECT t.id
, t.type
, t.points
-- , s.tot_points_by_type
, ROUND(t.points * 100.0 / s.tot_points_by_type,1) AS `%type`
FROM onetable t
JOIN ( SELECT r.type
, SUM(r.points) AS tot_points
FROM onetable r
GROUP BY r.type
) s
ON s.type = t.type
ORDER BY t.id
To do that same result with the subquery, that's going to be a correlated subquery, and that subquery is likely to get executed for every row in t.
This is why it's more natural for me to use a join operation, rather than a subquery in the SELECT list... even when a subquery works the same. (The patterns we use for more complex queries, like assigning aliases to tables, qualifying all column references, and formatting the SQL... those patterns just work their way back into simple queries. The rationale for these patterns is kind of lost in simple queries.)
try like this
select id,code,points,(points * 100)/(select sum(points) from tabel1) from table1
To add to a good list of responses, this should be fast performance-wise, and rather easy to understand:
DECLARE #T TABLE (ID INT, code VARCHAR(256), Points INT)
INSERT INTO #T VALUES (1,'101',2), (2,'201',3),(3,'233',4), (4,'123',1)
;WITH CTE AS
(SELECT * FROM #T)
SELECT C.*, CAST(ROUND((C.Points/B.TOTAL)*100, 2) AS DEC(32,2)) [%_of_TOTAL]
FROM CTE C
JOIN (SELECT CAST(SUM(Points) AS DEC(32,2)) TOTAL FROM CTE) B ON 1=1
Just replace the table variable with your actual table inside the CTE.
Can I write something like below. But this is not giving proper output in WinSQL/Teradata
with
a (x) as ( select 1 ),
b (y) as ( select * from a )
select * from b
Do you really need to use CTEs for this particular solution when derived tables would work as well:
SELECT B.*
FROM (SELECT A.*
FROM (SELECT 1 AS Col1) A
) B;
That being said, I believe multiple CTEs are available in Teradata 14.10 or 15. I believe support for a single CTE and the WITH clause were introduced in Teradata 12 or 13.
You call the dependent 1st and then the parent
like this and it will work. Why is it like that ? Teradata likes people to play with it longer and spend more time with it, making it feel important
with
"b" (y) as ( select * from "a" ),
"a" (x) as ( select '1' )
select * from b
I m selecting data from two different tables with no matching columns using this sql query
select * from (SELECT s.shout_id, s.user_id, s.time FROM shouts s
union all
select v.post_id, v.sender_user_id, v.time from void_post v)
as derived_table order by time desc;
Now is there any other way or with this sql statement only can i
differentiate the data from the two tables.
I was thinking of a dummy row that can be created at run-time(in the select statement only ) which would flag the row from the either tables.
As there is no way i can differentiate the shout_id that is thrown in the unioned table is
shout_id from the shout table or from the void_post table.
Thanks
Pradyut
You can just include an extra column in each select (I'd suggest a BIT)
select * from
(SELECT s.shout_id, s.user_id, s.time, 1 AS FromShouts FROM shouts s
union all
select v.post_id, v.sender_user_id, v.time, 0 AS FromShouts from void_post v)
as derived_table order by time desc;
Sure, just add a new field in your select statement called something like source with a different constant value for each source.
SELECT s.shout_id, s.user_id, s.time, 'shouts' as source FROM shouts s
UNION ALL
SELECT v.post_id, v.sender_user_id, v.time, 'void_post' as source FROM void_post v
A dummy variable is a nice way to do it. There isn't much overhead in the grand scheme of things.
p.s., the dummy variable represents a column and not a row.