Is it possible to order a query result based on 2 columns with the first sorting ascending on column1 and the secondary sort on column2 in desc?
select * from table1 orderby column1, column2
I believe this SQL statement should work, would adding desc along with the second column work or is there any better way of doing it?
yes
select * from table1 orderby column1 asc , column2 desc
Related
The table looks like
column1 column2 column3
400196 2021-07-06 33
400196 2021-07-06 33
400196 2021-08-16 33
I want to get the sum of column3 values based on grouping of column 1 but the duplicate values of date should not be added
The desired output is:
column1 column3
400196 66
The query I wrote is
select sum(column3)
from table_name
group by column1
But this gives me result 99
You can remove duplicate values in a subquery:
select t.column1, sum(t.column3)
from (select distinct t.column1, t.column2, t.column3
from t
) t
group by t.column1;
Note: This sort of problem can arise when you are joining tables together. Removing duplicates may not always be the right solution. Often it is better to do the calculation before joining, so you don't have duplicate values to deal with.
You could use a two step process here, first remove duplicates, then aggregate and sum:
SELECT column1, SUM(column3) AS column3
FROM (SELECT DISTINCT column1, column2, column3 FROM yourTable) t
GROUP BY column1;
Demo
Let's say I have table like this:
Column1 Column2
C 2
B 1
A 3
I need to exchange values in the second column to get this:
Column1 Column2
C 3
B 2
A 1
The goal is only for numeric column to have values sorted to follow alphabetical order on another column. The actual table has multiple columns and column 1 is people's name, while column 2 two is rank for rendering column 1 values in UI.
What is the most optimal way to do this?
I am doing this from C# code, on SQL server and have to use System.Data.SqlClient.SqlCommand because of transaction. But maybe it's not important if this can all be done from SQL.
Thank you!
So you need to update Column2 with the row-number according toColumn1?
You can use ROW_NUMBER and a CTE:
WITH CTE AS
(
SELECT Column1, Column2, RN = ROW_NUMBER() OVER (ORDER BY Column1)
FROM MyTable
)
UPDATE CTE SET Column2 = RN;
This updates the table MyTable and works because the CTE selects a single table. If it contains more than one table you have to JOIN the UPDATE with the CTE.
Demo
I am trying to find the SUM of column1 of all Distinct values of column2. Is it possible?
You could try something like this:
Select SUM(ColA), ColB
from table
Group by ColB
You almost wrote the query yourself in that sentence:
SELECT Column2, SUM(Column1) FROM Table GROUP BY Column2
It's not entirely clear what you're asking...
...this adds all the values in column 1 for each distinct value in column 2 then gives a total of all values in column 1:
SELECT Column2,SUM(Column1) FROM Table GROUP BY Column2 with rollup
Note: If you want the rollup at the top of the output put distinct in it.
SELECT distinct Column2,SUM(Column1) FROM Table GROUP BY Column2 with rollup
I need to return values in a column where only the unique values are returned. I know that DISTINCT will return only unique values, however i need to completely omit any that are duplicated.
i.e.
Column 1 Column 2
----------------------
123456789 27/02/2014
123456789 25/02/2014
654789897 27/02/2014
To return only "654789897 27/02/2014" and omit the other results.
You want to use group by and having:
select column1, column2
from table t
group by column1, column2
having count(*) = 1;
EDIT: (based on comment by knkarthick24)
Depending on what the OP intends, this might also be correct:
select column1, max(column2)
from table t
group by column1
having count(*) = 1;
select column1,column2
from tbl
where column1 in(
select column1
from table
group by column1 having count(column1)=1)
Its good to have Having and GroupBy
Let me know if that works:)
I have a series of select count queries tied together by UNION egg
Select Count(Column1) From Table1 where Table1 column1 = 1
union
Select Count(Column2) From Table1 where Table1 column2 = 1
It works fine but it just orders in asc or desc order but I want it to go in order by which I requested, I want the first query to always be first in the result no matter what the value is. Thanks for any help.
Run two queries?
You can add a column and sort on it
Select 1 as sequence, Count(Column1) From Table1 where Table1 column1 = 1
union
Select 2 as sequence, Count(Column2) From Table1 where Table1 column2 = 1
ORDER BY sequence
Try this:
SELECT COUNT(*) AS cnt, 1 AS SortOrder FROM Table1 WHERE column1 = 1
UNION ALL
SELECT COUNT(*) AS cnt, 2 AS SortOrder FROM Table1 WHERE column2 = 1
ORDER BY SortOrder
The main change I have made is to add a column which you can use to ORDER BY. Some of the other changes I have made:
You don't mean UNION, you mean UNION ALL. Otherwise with your query if the counts were the same you'd only get one row. In the new query this wouldn't happen, but you should still use UNION ALL because that's semantically what you mean.
Writing COUNT(column1) is unnecessary because your WHERE clause guarantees that column1 can never be NULL. Use COUNT(*). I imagine that even if you write COUNT(column1) most databases will see that column1 cannot be NULL and omit the unnecessary NULL check, but again there is nothing wrong with being explicit - you want to count all rows and COUNT(*) makes that clear.
You shouldn't have Table1 column1 with a space between. There should be a dot. Or simply omit the table name as it is not required here.