I am trying to join/concatenate 2 tables, because it would be more comfortable to work because they have the "year-month" column in common. As you can see below:
I just have 1 table uploaded in Qlik Sense, the 1st one. And I'm trying to upload the 2nd one to just one table. There would be no point in having to move the "year-month" period in the columns 2 times.
I'm using only expressions and the tables have the relation year-month.
Any ideas?
With Only Expressions
It might be tricky because what you're trying to do is typically handled prior to going to the front-end. If you're only trying to easily work with the data and selecting it, add the two separate tables as a master item (whatever chart you would like) then add that chart to your sheet. That will allow you to call one chart data set.
Ultimately, it doesn't solve your problem, but it's the best you're going to have if you want to use only expressions.
Combining the Tables
I think is your intent: use the data load script. The data load script is a simple SQL-like script that executes when the "load data" button is pressed. Here you can make columns, do math, join tables, split tables, do whatever you want.
Information about the script loader:
https://help.qlik.com/en-US/sense/February2020/Subsystems/Hub/Content/Sense_Hub/Scripting/introduction-data-modeling.htm
It seems like you're trying to do is an outer join. Qlik data load script syntax reserved word for outer joins is simply join --It's an outer join by default.
At its core, you would simply have something like this:
LOAD * from table1.csv;
join LOAD a, d from table2.csv;
Related
I'm using Grafana v9.3.2.2 on Azure Grafana
I have a line chart with labels of an ID. I also have an SQL table in which the IDs are mapped to simple strings. I want to alias the IDs in the label to the strings from the SQL
I am trying to look for a transformation to do the conversion.
There is a transformation called “rename by regex”, but that will require me to hardcode for each case. Is there something similar with which I don't have to hardcode for each case.
There is something similar for variables - https://grafana.com/blog/2019/07/17/ask-us-anything-how-to-alias-dashboard-variables-in-grafana-in-sql/. But I don't see anything for transformations.
Use 2 queries in the panel - one for data with IDs and seconds one for mapping ID to string. Then add transformation Outer join and use that field ID to join queries results into one result.
You may need to use also Organize fields transformation to rename, hide unwanted fields, so only right fields will be used in the label at the end.
I've tried by using some methods such as query, and pivot table, but looks like there are not way to add a lot of columns into a single one, any suggestion?
a Generic question..
I have an employee Table(EMPMAST) which has the New as well old Employee data. There is a flag called Current? which is 'Y' if he/she is a current employee.
Now I have to select records in my SQLRPGLE with only the current records and also some other criteria's(For Example EMPNAME = 'SAM') .What is the best way to deal with it. (in terms of performance and system usage)
To create a View over the EMPMAST with Current? = 'Y'. Then use it in the program with other conditions.
Use a CTE(With AS) in the Program which would have the Condition Current = 'Y' and use it.
use the table directly without CTE and View
any other option
Options 1, 2 and 3 would all perform the same. They would likely all have the same optimized query and access plan.
A CTE vs. a View are two different things. A View would be appropriate for a query that is going to be used in multiple locations, A CTE is only available in the query in which it is defined. I usually don't use the CTE except to replace a complex subquery. In your case the condition is simple enough to be contained in the where clause so I don't see the need to introduce additional complexity.
Some folks will tell you not to query the table directly in the program, but to always use a view. That way you add an extra layer of insulation between the program and the database, and you can still define record structures with ExtName, and not have to worry about changes to the table unless they affect the view itself. In this case you would likely have a dedicated view for each program that uses the table.
I tend to just use a hybrid of these techniques. I query tables, CTE's, or Views depending on the situation, and define my record structures explicitly in the program. I prefer to just query the table, but if I have some complex query logic which is unique to the program, I will use a CTE. I do have a few Views, but these are limited to those queries that happen in multiple programs where I want to ensure the same logic is applied consistently.
I have a handful of data sources that I'd like to apply the same analyses to and eventually load into a larger table database (uniformtable). Different sources contain different columns, and sometimes sources involve crosswalk files that I need to join. I'd like to have one query that converts all sources' data into uniformtable formatting, based on a unique key for each source. Something along the lines of this:
case when source.sourceid = 1 then
create uniformtable as
select column1a as uniforma, column1b as uniformb, sourceid from source
else
when source.sourceid = 2 then
create uniformtable as
select column2a as uniforma, column2b as uniformb, sourceid from source
end;
I've tried using if-then and case-when to accomplish this, but I get syntax errors pointing to the very start of my query. Does Redshift allow you to use if logic for this kind of control?
No, this logic is not permitted.
CASE statements are only valid within a SELECT statement.
You would need to perform this logic external to Amazon Redshift, and then just send the final SQL to create the table.
I am currently experimenting with Tableau Extract API to generate some TDE from the tables I have in a PostgreSQL database. I was able to write a code to generate the TDE from single table, but I would like to do this for multiple joined tables. To be more specific, if I have two tables that are inner joined by some field, how would I generate the TDE for this?
I can see that if I am working with small number of tables, I could use a SQL query with JOIN clauses to create a one gigantic table, and generate the TDE from that table.
>> SELECT * FROM table_1 INNER JOIN table_2
INTO new_table_1
ON table_1.id_1 = table_2.id_2;
>> SELECT * FROM new_table_1 INNER JOIN TABLE_3
INTO new_table_2
ON new_table_1.id_1 = table_3.id_3
and then generate the TDE from new_table_2.
However, I have some tables that have over 40 different fields, so this could get messy.
Is this even a possibility with current version of the API?
You can read from as many tables or other sources as you want. Or use complex query with lots of joins, or create a view and read from that. Usually, creating a view is helpful when you have a complex query joining many tables.
The data extract API is totally agnostic about how or where you get the data to feed it -- the whole point is to allow you to grab data from unusual sources that don't have pre-built drivers for Tableau.
Since Tableau has a Postgres driver and can read from it directly, you don't need to write a program with the data extract API at all. You can define your extract with Tableau Desktop. If you need to schedule automated refreshes of the extract, you can use Tableau Server or its tabcmd command.
Many thanks for your replies. I am aware that I could use Tableau Desktop to define my extract. In fact, I have done this many times before. I am just trying to create the extracts using the API, because I need to create some calculated fields, which is near impossible to create using the Tableau Desktop.
At this point, I am hesitant to use JOINs in the SQL query because the resulting table would look too complicated to comprehend (some of these tables also have same field names).
When you say that I could read from multiple tables or sources, does that mean with the Tableau Extract API? At this point, I cannot find anywhere in this API that accommodates multiple sources. For example, I know that when I use multiple tables in the Tableau Desktop, there are icons on the left hand side that tells me that the extract is composed of multiple tables. This just doesn't seem to be happening with the API, which leaves me stranded. Anyways, thank you again for your replies.
Going back to the topic, this is something that I tried few days ago on my python code
try:
tdefile= tde.Extract("extract.tde")
except:
os.remove("extract.tde")
tdefile = tde.Extract("extract.tde")
tableDef = tde.TableDefinition()
# Read each column in table and set the column data types using tableDef.addColumn
# Some code goes here...
for eachTable in tableNames:
tableAdd = tdeFile.addTable(eachTable, tableDef)
# Use SQL query to retrieve bunch_of_rows from eachTable
for some_row in bunch_of_rows:
# Read each row in table, and set the values in each column position of each row
# Some code goes here...
tableAdd.insert(some_row)
some_row.close()
tdefile.close()
When I execute this code, I get the error that eachTable has to be called "Extract".
Of course, this code has its flaws, as there is no where in this code that tells how each table are being joined.
So I am little thrown off here, because it doesn't seem like I can use multiple tables unless I use JOINs to generate one table that contains everything.