I am a beginner for SQL.
If I have a table tab like blow:
In R, I can use table(tab$prediction, tab$result_code) to get the table which look like confusion table. But I don't known how to create this table by using SQL command. Is it possible to get the table contain counts between prediction column and result_code column?
From your data, the column "prediction" was used as the actual prices and the "result_code" column as predicted values.
As the comments advise, you can perform a COUNT over the two columns to get the occurrences. This table is used as the base to create the confusion matrix and is names as TEMP.
After creating the TEMP table, you perform a PIVOT to restructure the table to get the format of the confusion matrix.
SELECT prediction, "0", "1", "2"
FROM
(
SELECT [prediction],[result_code],COUNT(*) as Occurences
FROM [Your_Schema].[dbo].[Your_Database]
GROUP BY [prediction],[result_code]
)Temp
PIVOT
(
MAX(Occurences)
FOR result_code in ("0","1","2")
)PIV
Related
I have a table that has just a code for the individual column name like "A1G", "Z8H" etc.
This table is a really huge table. Therefore it would not help to manually add the alias name in the SELECT Statement like.
The description for each column code is stored in a different table:
Now I would like to SELECT * from the first table but with the right column header name.
This is stored in the second table within the filters Schema = 'ABC' and Table = 'A'.
That would be desired output:
How would you do that in SQL?
How can I change the column name?
You would be better off just creating a view with all the columns aliased to your preferred names. Once that's done you can select from the view and get the data back with the headings you want.
Look into Inner Join
Or Left Join.
Is there a way that after comparing two tables and then use the Case function?
I am trying to have a new column base on Exists transformation. In sql I do it like this:
(isnull (select 'YES' from sales where salesperson = t1.salesperson group by salesperson), 'NO')) AS registeredSales
T1 is personal.
Or should I include the table into the stream of the joins and then use the case() function to compare the two columns?
If there's another way to work around to compare these two streams, I would be pleased to hear.
Thanks.
Flat files in a datalake can also be compared. We can use the derived column in dataflow to gernerate a new column.
I create a dataflow demo cotains two sources: CustomerSource(customer.csv stored in datalake2) and SalesSource(sales.csv stored in datalake2 and it contains only one column) as follows
Then I join the two sources with the column CustomerId
Then I use Select activity to give an alias to the CustomerId from SalesSource
In the DerivedColumn, I select the Add column and enter the expression iifNull(SalesCustomerID, 'NO', 'YES') to generate a new column named 'registeredSales' as follows:
The last column of the result shows:
In a table called payouts, there is a column stripeResponseData where the data is in the following structure:
{"id":"tr_1BlSHbGQXLV7RqqnHJffUVO0","object":"transfer","amount":39415,"amount_reversed":0,"balance_transaction":"txn_1BlSHbGQXfV7AqqnGi2o7UiY","created":1516239215,"currency":"usd","description":null,"destination":"acct_1BWWAmAzms5xPfV9","destination_payment":"py_1BlSHbAzms5xkfV91RHAOrno","livemode":true,"metadata":{},"reversals":{"object":"list","data":[],"has_more":false,"total_count":0,"url":"/v1/transfers/tr_1BlSHbYQXLV7AqqnHJffUVO0/reversals"},"reversed":false,"source_transaction":null,"source_type":"card","transfer_group":null}
Within my SQL SELECT statement, I want to return only the value of the key "destination". How do I write my SQL query?
My desired result of the query:
SELECT "stripeResponseData" FROM payouts [...]
(where I don't know how to write [...]) should look like the following (assume we have 3 rows with different values on "destination"):
acct_1BWWAmAzms5xPfV9
acct_1AY0phDc9pCDpLR8
acct_1AwG3VL7DXxftOaS
How do I extract that value from the list within the stripeResponseData column?
See this sqlfiddle. This query will fetch the ID from stripResponseData where the id is a specific id (Probably not very useful, but does show you how to select and query):
SELECT data->>'id' FROM stripeResponseData WHERE data #> '{"id":"tr_1BlSHbGQXLV7RqqnHJffUVO0"}';
Because you mentioned your data was a string, you need to to type conversions to query/use it correctly. See this sqlfiddle:
SELECT data::jsonb->>'id' FROM stripeResponseData WHERE data::jsonb #> '{"id":"tr_1BlSHbGQXLV7RqqnHJffUVO0"}';
Per your edit, you can simply query destination in almost the exact same way. This will get all the id's from stripeResponseData where destination = acct_1BWWAmAzms5xPfV9:
SELECT data::jsonb->>'id' FROM stripeResponseData WHERE data::jsonb #> '{"destination":"acct_1BWWAmAzms5xPfV9"}';
This is the query I'm trying.
EVALUATE
SELECTCOLUMNS('MyTable',"col1",DISTINCT(VALUES('MyTable'[Email])))
If you are trying to simply create a new, single column table with the distinct values of an existing table, you can use the formula below.
Starting with data like this...
... simply create a new table with this formula to get a list of distinct values.
Locations = DISTINCT(Fruit[Location])
This will work:
Evaluate
VALUES('Table'[Column])
I have the following table structure in SQL (using T-SQL):
sqlfiddle: http://sqlfiddle.com/#!6/e5edc/1/0
The data would look something like this:
Now I would like to transpose the structure so I get the following:
columns [01_amount] to [12_amount] and columns [01_active] to [12_active] as rows instead of columns
All rows of [initials] to be separate columns
Should look like this:
How would I go about this? The Pivot function looks rather complicated as I'm new to SQL. Can someone help me in the right direction? :-)
Ok you will need first to unpivot your data, which is done in cte. Then you will need to pivot again:
;with cte as(select initials, v, col from main
unpivot(v for col in([01_amount], [02_amount])) u)
select * from cte
pivot(max(v) for initials in([rw],[nb]))p
In unpivot part just add all 24 column names for amounts and active bits. In pivot part just add all possible values for initials.
But if you don't want to manually list all possible values for initials then you will need to make some dynamic query with unpivoting and pivoting.
Here is demo for 2 columns and you will easily expand it http://sqlfiddle.com/#!6/4cf36/2