I want to swap 2nd and 3rd column of one table using CTE.
I'm working with below query, which keeps throwing an error,
no such column: cte.comm1
Table - [SalComm] column: ID, Sal, Comm
with CTE as
(
SELECT ID as id1, sal as sal1, comm as comm1 from SalComm
) UPDATE SalComm SET sal=cte.comm1, comm=cte.sal1 where ID= cte.id1*
Could you please suggest to me the right query?
This answer assumes you are using SQL Server, or some other database, which supports directly updating common table expressions. I don't see the point at all of the aliases inside your CTE. If you want to swap columns values, just use the direct columns names:
WITH cte AS (
SELECT ID, sal, comm
FROM SalComm
)
UPDATE cte
SET sal = comm, comm = sal;
-- no WHERE clause needed, if you really want to cover the entire table
That being said, you could just as easily do the above update on the original table. Updatable CTEs are more useful when they generate some complex derived results which you intend to use as part of a later update. That does not appear to be the case here.
Related
I have a customers table with ID's and some datetime columns. But those ID's have duplicates and i just want to Analyse distinct ID values.
I tried using groupby but this makes the process very slow.
Due to data sensitivity can't share it.
Any suggestions would be helpful.
I'd suggest using ROW_NUMBER() This lets you rank the rows by chosen columns and you can then pick out the first result.
Given you've shared no data or table and column names here's an example based on the Adventureworks database. The technique will be the same, you partition by whatever makes the group of rows you want to deduplicate unique (ProductKey below) and order in a way that makes the version you want to keep first (Children, birthdate and customerkey in my example).
USE AdventureWorksDW2017;
WITH CustomersOrdered AS
(
SELECT S.ProductKey, C.CustomerKey, C.TotalChildren, C.BirthDate
, ROW_NUMBER() OVER (
PARTITION BY S.ProductKey
ORDER BY C.TotalChildren DESC, C.BirthDate DESC, C.CustomerKey ASC
) AS CustomerSequence
FROM dbo.FactInternetSales AS S
INNER JOIN dbo.DimCustomer AS C
ON S.CustomerKey = C.CustomerKey
)
SELECT ProductKey, CustomerKey
FROM CustomersOrdered
WHERE CustomerSequence = 1
ORDER BY ProductKey, CustomerKey;
you can also just sort the columns with date column an than click on id column and delete duplicates...
I have the following query in M:
= Table.Combine({
Table.Distinct(Table.SelectColumns(Tab1,{"item"})),
Table.Distinct(Table.SelectColumns(Tab2,{"Column1"}))
})
Is it possible to get it working without prior changing column names?
I want to get something similar to SQL syntax:
select item from Tab1 union all
select Column1 from Tab2
If you need just one column from each table then you may use this code:
= Table.FromList(List.Distinct(Tab1[item])
& List.Distinct(Tab2[Column1]))
If you use M (like in your example or the append query option) the columns names must be the same otherwise it wont work.
But it works in DAX with the command
=UNION(Table1; Table2)
https://learn.microsoft.com/en-us/dax/union-function-dax
It's not possible in Power Query M. Table.Combine make an union with columns that match. If you want to keep all in the same step you can add the change names step instead of tap2 like you did with Table.SelectColumns.
This comparison of matching names is to union in a correct way.
Hope you can manage in the same step if that's what you want.
I have two tables (CompletedJobs & ScriptDetails) and using DAX, I want to return distinct Names that appear in CompletedJobs that do not appear in ScriptDetails.
Here is my SQL Query. Works and return values.
Select Distinct CJ.[Name]
From CompletedJobs CJ
Left Join ScriptDetails SD
ON CJ.[Name]=SD.ActivityName
Where SD.ActivityName IS NULL
I started with creating the following DAX query, but just doing this, I get the following error message:
"A table of multiple values was supplied where a single value was expected"
AdhocJobs = DISTINCT(UNION(SELECTCOLUMNS(CompletedJobs,"Name",CompletedJobs[Name]),SELECTCOLUMNS(ScriptDetails,"Name",ScriptDetails[ActivityName])))
How do I create a DAX query that would replicate the SQL query?
Rather than recreate your SQL, there is DAX that already addresses your specific use case. The EXCEPT function returns a table where rows from the LEFT SIDE table do not appear in the RIGHT SIDE table.
EVALUATE
DISTINCT (
EXCEPT (
SUMMARIZE ( CompletedJobs , CompletedJobs [Name]),
SUMMARIZE ( ScriptDetails , ScriptDetails [ActivityName])
)
)
In this case I used SUMMARIZE to reduce each table down to one column, and then wrapped them with EXCEPT to take only the Names from Completed Jobs that aren't ActivityNames in ScriptDetails.
Hope it helps.
From
https://cloud.google.com/bigquery/docs/partitioned-tables:
you can shard tables using a time-based naming approach such as [PREFIX]_YYYYMMDD
This enables me to do:
SELECT count(*) FROM `xxx.xxx.xxx_*`
and query across all the shards. Is there a special notation that queries only the latest shard? For example say I had:
xxx_20180726
xxx_20180801
could I do something along the lines of
SELECT count(*) FROM `xxx.xxx.xxx_{{ latest }}`
to query xxx_20180801?
SINGLE QUERY INSPIRED BY Mikhail Berlyant:
SELECT count(*) as c FROM `XXX.PREFIX_*` WHERE _TABLE_SUFFIX IN ( SELECT
SUBSTR(MAX(table_id), LENGTH('PREFIX_') + 2)
FROM
`XXX.__TABLES_SUMMARY__`
WHERE
table_id LIKE 'PREFIX_%')
If you do care about cost (meaning how many tables will be scaned by your query) - the only way to do so is to do in two steps like below
First query
#standardSQL
SELECT SUBSTR(MAX(table_id), LENGTH('PREFIX') + 1)
FROM `xxx.xxx.__TABLES_SUMMARY__`
WHERE table_id LIKE 'PREFIX%'
Second Query
#standardSQL
SELECT COUNT(*)
FROM `xxx.xxx.PREFIX_*`
WHERE _TABLE_SUFFIX = '<result of first query>'
so, if result of first query is 20180801 so, second query will obviously look like below
#standardSQL
SELECT COUNT(*)
FROM `xxx.xxx.PREFIX_*`
WHERE _TABLE_SUFFIX = '20180801'
If you don't care about cost but rather need just result - you can easily combine above two queries into one - but - again - remember - even though result will be out of last table - cost will be as you query all table that match xxx.xxx.PREFIX_*
Forgot to mention (even though it should be obvious): of course when you have only COUNT(1) in your SELECT - the cost will be 0(zero) for both options - but in reality - most likely you will have something more valuable than just count(1)
I know this is a kind of an old thread but I was surprised why no one offers an answer using Variables.
"Héctor Neri" already mentioned this in the comments but I thought might be better to have an actual answer with a sample code posted.
#standardSQL
DECLARE SHARD_DATE STRING;
SET SHARD_DATE=(
SELECT MAX(REPLACE(table_name,'{TABLE}_',''))
FROM `{PRJ}.{DATASET}.INFORMATION_SCHEMA.TABLES`
WHERE table_name LIKE '{TABLE}_20%'
);
SELECT * FROM `{PRJ}.{DATASET}.{TABLE}_*`
WHERE _TABLE_SUFFIX = SHARD_DATE
Make sure to replace {PRJ}, {DATASET}, and {TABLE} values with your table location.
If you run this on BigQuery Web UI, you will see this message:
WARNING: Could not compute bytes processed estimate for script.
But you can see that variable properly reduce the table scan to the latest partition and does not cause any extra cost after running the script.
In my model I have table AssignedToUser that don't contain any NULL values.
Table TotalCounts contains number of tasks for each User.
Those two table joined on UserGUID, and table TotalCounts contains NULL value for UserGUID.
When I drop everything in one table there is NULL value for AssignedToUser.
How can I substitute value NULL for AssignedToUser for "POOL".
Under EditQuery I tried to Create additional column
if [AssignedToUser] = null then "POOL" else [AssignedToUser]
But that didnt help.
UPDATE:
Thanks Alexis.
I have created FullAssignedToUsers table, but when I try to make a relationship with TotalCounts on UserGUID - it doesnt like it.
Data in new a table looks like this:
UPDATE:
File .ipbx can be accessed here:
https://www.dropbox.com/s/95frggpaq6tce7q/User%20Open%20Closed%20Tasks%20Experiment.pbix?dl=0
I believe the problem here is that your join has UserGUID values that are not in your AssignedToUsers table.
To correct this, one possibility is to replace your AssignedToUsers table with one that contains all the UserGUID values from the TotalCounts table.
FullAssignedToUsers =
ADDCOLUMNS(VALUES(TotalCounts[UserGUID]),
"AssignedToUser",
LOOKUPVALUE(AssignedToUsers[AssignedToUser],
AssignedToUsers[UserGUID], TotalCounts[UserGUID]))
The should get you the full outer join. You can then create the custom column like you described in the table and use that column in your visual.
You'll probably want to break the relationships with the original AssignedToUsers table and create relationships with the new one instead.
If you don't want to take that extra step, you can do an ISBLANK inside your new table formula.
FullAssignedToUsers =
ADDCOLUMNS(VALUES(TotalCounts[UserGUID]),
"AssignedToUser",
IF(
ISBLANK(
LOOKUPVALUE(AssignedToUsers[AssignedToUser],
AssignedToUsers[UserGUID], TotalCounts[UserGUID])),
"POOL",
LOOKUPVALUE(AssignedToUsers[AssignedToUser],
AssignedToUsers[UserGUID], TotalCounts[UserGUID])))
Note: This is equivalent to doing a right outer join merge on the AssignedToUsers table in the query editor and then replacing the nulls with "POOL". I'd actually recommend approaching it that way instead.
Another way to approach it is to pull the AssignedToUser column over to the TotalCounts table in a custom column and use that column in your visual instead.
AssignedToUsers =
IF(ISBLANK(RELATED(AssignedToUsers[AssignedToUser])),
"POOL",
RELATED(AssignedToUsers[AssignedToUser]))
This is equivalent to doing a left outer join merge on the TotalCounts table in the query editor, expanding the AssignedToUser column, then replacing nulls with "POOL" in that column.
In Dax missing values are Blank() not null. Try this:
=IF(
ISBLANK(AssignedToUsers[AssignedToUser]),
"Pool",
AssignedToUsers[AssignedToUser]
)