Basic SQL: selecting AVG() values depending upon two columns - sql-server

I want to get AVG values, depending upon the values of two columns.
Here is my table example:
And this is what I need to get:
I'm using that code to get required data but it gives me average for issue not issue and owner.
Here is my code;
select issue, owner, AVG(time) from myTable group by issue, owner
Any suggestion about that?

You can use below query
select issue, owner, avg(time) over() from mytable

Related

snowflake merge statement using golden gate json as source table

while executing target table in snowflake using json data as source table
merge into cust tgt using (
select parse_json(s.$1):application_num as application num
from prd_json s qualify
row_number() over(partition application
order_by application desc)=1) src
on tgt.application =src.application
when not matched and op_type='I' then
insert(application) values (src.application );
qualify commands ignores all the duplicate data present and gives only unique record but while putting joins its show only less records when compare to normal select statement.
for example :
select distinct application
from prd_json where op_type='I';
--15000 rows are there
while putting joins it shows there is not matching records in target . if it is not matched it should insert all 15000rows but 8500 rows only inserting even though it was not an duplicate record . is there any function available without using "qualify" shall we insert the record. if i ignore qualify am getting dml error duplication. pls guide me if anyone knows.
How about using SELECT DISTINCT?
You demo SQL does not compile. and you using the $1 means it's also hard to guess the names of your columns to know how the ROW_NUMBER is working.
So it's hard to nail down the problem.
But with the following SQL you can replace ROW_NUMBER with DISTINCT
CREATE TABLE cust(application INT);
CREATE OR REPLACE table prd_json as
SELECT parse_json(column1) as application, column2 as op_type
FROM VALUES
('{"application_num":1,"other":1}', 'I'),
('{"application_num":1,"other":2}', 'I'),
('{"application_num":2,"other":3}', 'I'),
('{"application_num":1,"other":1}', 'U')
;
MERGE INTO cust AS tgt
USING (
SELECT DISTINCT
parse_json(s.$1):application_num::int as application,
s.op_type
FROM prd_json AS s
) AS src
ON tgt.application = src.application
WHEN NOT MATCHED AND src.op_type = 'I' THEN
INSERT(application) VALUES (src.application );
number of rows inserted
2
SELECT * FROM cust;
APPLICATION
1
2
running the MERGE code a second time gives:
number of rows inserted
0
Now if truncate CUST and I swap to using this SQL for the inner part:
SELECT --DISTINCT
parse_json(s.$1):application_num::int as application,
s.op_type
FROM prd_json AS s
qualify row_number() over (partition by application order by application desc)=1
I get three rows inserted, because the partition by application, is effectively binding to the s.application not the output application, and there are 3 different "applications" because of the other values.
The reason I wrote my code this way is your
select distinct application
from prd_json where op_type='I';
implies there is something called application already, in the table.. and thus it runs the chance of being used in the ROW_NUMBER statement..
Anyways, there is a large possible problem is you also have "update data" I guess U in your transaction block, that you want to ORDER BY the sub-select so you never have a Inser,Update trying action in Update,Inser order. And assuming you want all update operations if there are many of them.. I will stop. But if you do not have Updates, the sub-select should have the op_type='I' to avoid the non-insert ops making it. Out, or possible worse again, in your ROW_NUMBER pattern replacing the Intserts. Which I suspect is the underlying cause of your problem.

How do I Select an aggregate function from a temp table without getting the invalid column error from not including the column in the GROUP BY clause?

I performed aggregate functions in a temp table but I'm getting an error because the field I performed the aggregate function on is not included in a GROUP BY in the table I am selecting from. To clarify, this is just a snippet so these tables are temp tables in the larger query. They are also named in the actual code.
WITH #t1 AS
(SELECT
Name,
Date,
COUNT(Email),
COUNT(DISTINCT Email)
FROM SentEmails)
SELECT
#t1.*,
#t2.GrossSents
FROM #t1
--***JOINS***
GROUP BY
#t1.Name,
#t1.Date
I expect a table with Name, Date, Count of Emails, Unique Emails, and Gross Sends fields but I get
Column '#t1.COUNT(Email)' is invalid in the select list` because it is not contained in either an aggregate function or the GROUP BY clause.
Break your issue into steps.
Start by getting the query inside your CTE to return the data you expect from it. The query as written here won't run because you're doing aggregation without a GROUP BY clause.
Once that query is giving you the results you want, wrap it in the CTE syntax and try a SELECT * FROM cteName to see if that works. You'll get an error here because each column in a CTE has to have a name and your last two columns don't have names. Also, as noted in the comments, it's a poor practice to name your CTE with a #. It makes the subsequent code more confusing, since it appears as though there's a temp table someplace, and there isn't.
After you have the CTE returning what you need, start joining other tables, one at a time. Monitor those results as you add tables so you're sure that your JOINs are working as you expect.
If you're doing further aggregation on the outer query, specifying SELECT * is just asking for trouble because you're going to need to specify every non-aggregated column in your GROUP BY anyway. As a general rule, you should enumerate your columns in your SELECT, and in this case that will allow you to copy & paste them to your eventual GROUP BY.

Select one column multiple time

I want to select one column two time from a table.
E.g
( Select rent as rent1, rent as rent2 From Expense)
But I don't know how I can Select this column multiple time as each has its own Where Clause.
Means I want to select One Column two time On two different condition.
Use a union
select test, 'rent1' from tableA where condA
union
select test, 'rent2' from tableA where condB
If you would want to have both values in one result line (can't think of a reason why you would want this, but anyway...) you could use something like a self-join:
select a.rent as rent1, b.rent as rent2
from Expense a,
Expense b
where a.condition
and b.condition
and a/b-join-condition

Paging in SQL Server problems

I have searched for paging in SQL Server. I found most of the solution look like that
What is the best way to paginate results in SQL Server
But it don't meet my expectation.
Here is my situation:
I work on JasperReport, for that: to export the report I just need pass the any Select query into the template, it will auto generated out the report
EX : I have a select query like this:
Select * from table A
I don't know any column names in table A. So I can't use
Select ROW_NUMBER() Over (Order By columsName)
And I also don't want it order by any columns.
Anyone can help me do it?
PS: In Oracle , it have rownum very helpful in this case.
Select * from tableA where rownum > 100 and rownum <200
Paging with Oracle
You should use ROW_NUMBER with an ORDER BY - because without an ORDER BY there is no determinism in how rows are returned. You can run the same query three times and get the results back in three different orders. Especially if merry-go-round scans come into play.
So unless you want your report to have the possibility of showing the same rows to users on multiple pages, or some rows never on any page, you need to find a way to order the result set to make it deterministic.
From my opinion, you can use sql query to find out how many columns in a table, and then find out a proper one for ' order by ' to depend on.
The script of how to get out columns of an table refer to : How can I get column names from a table in SQL Server?
Check out this link
http://msdn.microsoft.com/en-us/library/ms186734.aspx
SQL Server has similar function ROW_NUMBER. Though it behaves a bit differently.
SQL Server provides no guarantee of row order unless you have have specified a column in order by clause. I would recommend that you give an order by clause that has unique values.
Thank for all your help. Because of order by are required when paging in MS SQL Server, so I used ResultSetMetaData to get the Columns name and do paging as well.
You can use the below query aswell.
declare #test table(
id int,
value1 varchar(100),
value2 int)
insert into #test values(1,'10/50',50)
insert into #test values(2,'10/60',60)
insert into #test values(3,'10/60',61)
insert into #test values(4,'10/60',10)
insert into #test values(5,'10/60',11)
insert into #test values(6,'10/60',09)
select *
from ( select row_number() over (order by (select 0)) as rownumber,* from #test )test
where test.rownumber<=5

Count of Distinct Rows Without Using Subquery

Say I have Table1 which has duplicate rows (forget the fact that it has no primary key...) Is it possible to rewrite the following without using a JOIN, subquery or CTE and also without having to spell out the columns in something like a GROUP BY?
SELECT COUNT(*)
FROM (
SELECT DISTINCT * FROM Table1
) T1
You can do something like this.
SELECT Count(DISTINCT ProductName) FROM Products
but if you want a count of completely distinct records then you will have to use one of the other options you mentioned.
If you wanted to do something like you suggested in the question, then that would imply you have duplicate records in your table.
If you didn't have duplicate records SELECT DISTINCT * from table would be the same without the distinct.
No, it's not possible.
If you are limited by your framework/query tool/whatever, can't use a subquery, and can't spell out each column name in the GROUP BY, you are SOL.
If you are not limited by your framework/query tool/whatever, there's no reason not to use a subquery.
if you really really want to do that you can just "SELECT COUNT(*) FROM table1 GROUP BY all,columns,here" and take the size of the result set as your count.
But it would be dailywtf worthy code ;)
I just wanted to refine the answer by saying that you need to check that the datatype of the columns is comparable - otherwise you will get an error trying to make them DISTINCT:
e.g.
com.microsoft.sqlserver.jdbc.SQLServerException: The ntext data type cannot be selected as DISTINCT because it is not comparable.
This is true for large binary, xml columns and others depending on your RDBMS - rtm. The solution for SQLServer for example is to cast it from an ntext to an nvarchar(MAX) from SQLServer 2005 onwards.
If you stick to the PK columns then you should be OK (I haven't verified this myself but I'd have thought logically that PK columns would have to be comparable)

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