How to create queries dynamically based on filters selected in PostgreSQL? - postgresql

I have a UI where products of various categories will be listed. There will be filters on various attributes which users can select to filter out the products. How should I create a query which will change dynamically based on the selection of filters? Further, once the result set is ready, only few rows to be displayed at a time to the user e.g. 10 rows at a time; value of which again will be decided by the user.

You could write a PL/pgSQL function that takes a JSON with filter fields and values and returns matching rows. But there are libraries for doing that, why not use one of them. What is your UI built on?
On pagination, see Five ways to paginate in Postgres

Related

Filtering a datasource using multi select wild character

Does anyone know if there is a wildcard character in AppMaker that can be used for all possible values for a field in a query?
I currently have a datasource that is being filtered based on the status using a multi-select widget. What I would like to accomplish is when all values have been de-selected I want to load all the records of that datasource without clearing the entire query in case other filters have been applied. I have it working in-a-sense that I have to explicitly construct my query as such:
widget.datasource.query.filters.Status._in = ['Status Value 1','Status Value 2','Status Value 3']
My current solution is loading the correct data when a value is selected and it correctly shows the union of the query as the values are modified. However, it selects all of the values in my multi-select; which I know is how it is supposed to work.
I tried using widget.datasource.query.filters.Status._contains = ''; and changing the assignment value to no avail. I even tried the opposite approach using _notContains
The intended outcome is to have a filtering dashboard appear much like any website where when no filtering is selected all records are displayed. I was hoping to find a wildcard character that would load all of the records. Just trying to find a way to mimic other website filters with all records when none are selected.
Thanks for the time!
So the easiest solution here is to set up your Multiselect as follows:
Options binding:
#models.YourModel.fields.Status.possibleValues
or if you don't have the possible Status values in your model then set your options binding to:
['Status Value 1','Status Value 2','Status Value 3']
Values binding:
#datasource.query.filters.Status._in
Now anytime you select any choices in the multiselect, the query will only include records that include the selected choices. And if you deselect all choices the query will ignore that filter or treat it as an empty array of values, therefore returning all records unless you applied other filters.

How to filter dashboard based on quick filter values selected in Tableau ?

I'm having Dashboard-1 with the data source from SQL Server Table-A having columns
Col1,Col2,Col3
Now, i'm creating a new dashboard-2 with data source as Table-B having columns Col1,Col4,Col5.
But Col1 which is common in both these tables doesn't have common data.
Eg. Col1 from Table-A is having records till 100 and Table-B is having records from 101.Also, the data is not static, its keeps on increasing in Table-B , Table-A is no longer populating but we need the data from it.
Problem1-- How to merge two column as single column for filter in Tableau
Problem2-- in the dashboard i need to show single filter as a union of Col1 from both tables, if user select value <100 then Dashboard-1 will open otherwise Dashboard-2.
Can someone provide me a correct approach.
1) Instead of merging after you have brought the data in, try merging the data using SQL UNION.
2) If that's not possible, do the same after importing both the datasets into Tableau. For an example, try from this official link
3) Try different Joins to see which one works for merging your table columns:
4) If all the above fails, try setting up an Action Filter explained in this link. Essentially you have to use Tiled Containers instead of Floating Containers and set up a action filter using a custom Parameter. This custom Parameter will help display Dashboard 1 when user selects <100 in the filter(for example) and Dashboard 2 when user selects >100(again example)

Where are stored filter params in magento 2?

I need to export the products catalog after I applied a filter. I made a custom button for this, but in the query I need the filters already applied on the grid. Is it possible to get them from the global variable? I noticed that if I refresh the page, the filters are kept, but I do not know where they are from.
You can find applied filters data at the ui_bookmark table of your database;
SELECT `namespace`, `config` FROM `ui_bookmark`;

how to create multiple filters from one dimension tableau (10)?

I have a two dimensions with the following data set
Original Dimension
I would like to create two filters that can be used to filter my dashboard. These two filter would be called - "Product_Type" and "Product" and should have the following drop downs:
Filter Breakdown
To summarize, I am looking for a way to take my original dimension and create the filter breakdowns so that in my dashboard I can have two filter (Product_type and Product). When i click on the Product_type filter, i should be able to see "overall", "fruits", "vegetable" and "leafy. Based on my selection , the Product filter should automatically show only the relevant values - i.e. if i picked "leafy" it should only show "spinach" and "kale". Finally if i select "kale" my entire dashboard should change accordingly.
Looking for a way to do this without drastically affecting the performance.
update: i was able to achieve this by creating multiple parameters and then using the pop window technique (https://vimeo.com/107352893) - but this has affected my workbook performance very badly. Need another solution!!
You should be able to accomplish your desired functionality by creating a calculated field for product type and a CASE statement to classify the products based on the product type you specified your image.
Further, filters can be configured to display available values based on the other filters in place. I would recommend having your Product Type filter a the "context" or "data-source" level, and your product filter at the lowest level, so that the selectable options for the product filter can be displayed using the "only relevant Values" option and limits the products that can be chosen.
Please see the following link for some more information on filtering hierarchies
Performance Related
General Filtering
Blog Post
"Only relevant values - Specifies which values to show in the filter. When you select this option other filters are considered and only values that pass these filters are shown. For example, a filter on State will only show the Eastern states when a filter on Region is set. You can use the toggle at the top of the filter card to switch between this option and the All Values in Database option.
All values in database - Specifies which values to show in the filter. When you select this option all values in the database are shown regardless of the other filters on the view.
All values in context (Tableau Desktop only) - When one of the filters in the view is a context filter, select this option on a different filter to only display values that pass through the context filter. For more information, see Improve View Performance with Context Filters."

How to programmatically create ListView based off SQLite query?

I have some code that allows the user to perform a search by selecting a few checkboxes. A sql query is then created based on what checkboxes are checked. (Up to 5 checkboxes)
The data is then queried against a sqlite data.
The issue is now how do i populate the data into a listview (not knowing how many columns there will be ahead of time (Could be anywhere from 1 to 5)
All the examples I"ve seen is where the listView is created and you know exactly how many colummns are going to be returned.
A previous posted suggested to query all the records and then use if statements to determine if the value is null then hide column.