Solved: Conditions of nested SELECTs - Page 2

Joseph_Seddik · 07-31-2023 06:00 AM

Hello,

I have a scenario, where I would like to select a set of records based on a certain number of conditions AND also if the sum of a certain field in the SELECTED rows exceeds a certain threshold. For example, customers with a certain gross sales amount during a specific period.

I did this:

SELECT(theTable[customer],
AND(
[condition-1],
[condition-2],
[condition-3],
SUM( SELECT(theTable[sale],
[customer] = [_ThisRow-1].[customer]
)) > [_ThisRow].[threshold]
), true
)

This didn't give correct result since the inner SELECT operated on all rows ignoring the preceding the outer SELECT's conditions, while I expected it to only work on the rows already selected by the outer SELECT, as SQL maybe? especially with the presence of the [_ThisRow-1] clue.

So I did:

SELECT(theTable[customer],
AND(
[condition-1],
[condition-2],
[condition-3],
SUM( SELECT(theTable[sale], AND(
[customer] = [_ThisRow-1].[customer],
[condition-1],
[condition-2],
[condition-3]
))) > [_ThisRow].[threshold]
), true
)

This gave correct results as expected but the expression itself is very slow to execute. It is in a normal column, and just opening a form with line calculated takes over a minute. If the table has 1000 rows, ignoring the outer SELECT's conditions would make the calculation run 1 million times.

At the end I ditched it and built a specific table to do selection and referencing before hand.

Would you please share your thoughts? Would you expect the same behaviour? Do you think there are better ways/improvements? Thanks!

1minManager

So you are a bit stuck with how we have to write formulas with no option to store a value. A simplier form of the problem is

IF(
   [A]+[B]+[C]>=7,
   7,
   [A]+[B]+[C]
)

Ideally you want to do [A]+[B]+[C], save that as a variable, then use the variable in the formula. But lets not complain about what we don't have...

The best I can come up with for you is to use a slice to split it up a bit. Create a slice of theTable with

AND(
   [condition-1],
   [condition-2],
   [condition-3]
)

Then change your formula to:

SELECT(SLICE[customer],
   SUM(SELECT(SLICE[sale],[customer]=[_ThisRow-1].[customer]))>[_ThisRow].[threshold]
)

So the slice will run on sync. But like a variable, this happens only once and hopfully will be more efficent.

The only other addition is that I presume that with SUM(SELECT(SLICE[sale],[customer]=[_ThisRow-1].[customer])) you're adding up all the sales for each customer. Do you not have a seperate customer table you could do the sum on once? Or of this is simply a list of sale items, then consider using an action that calculates this on save. That way the forumla could be to find the last updated record for this customer and then extract [sale].

Simon, 1minManager.com

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Aurelien

Hi @Joseph_Seddik

From my point of view, your calculation runs twice on a huge dataset and it would be great being able to reduce it.

Just some thought to share for help, is it possible to restrict with an intermediate virtual column the dataset to evaluate, and run the calculations over it?

For example:

1) let's name [_restrictedTheTable]

FILTER("theTable",
  AND(
    [condition-1],
    [condition-2],
    [condition-3]
  )
)

2) Then, I would go with:

SELECT(theTable[customer],
  AND(
   IN([id],[_THISROW].[restrictedTable]),
    SUM( SELECT(theTable[sale], 
      AND(
        [customer] = [_ThisRow-1].[customer],
        IN([id],[_THISROW].[restrictedTable])
      )
    )) > [_ThisRow].[threshold]
  ), true
)

This is a minor change, I'm not sure that would be efficient.

However, using the Reference properties, it may be usefeul to use a set of actions as described by @1minManager to flag relations between your customer table and your selection table.

For example, you could create a new column [_restrictedCustomer], type List of Ref with the expression:

[restrictedTables][customer]

Doing this could be used to track the rows of table that matches your selection criteria and establish a relationship with the sales spent with your customer, regarding the threshold.

I don't know if there is a kind of SELECT([Related XXX], condition) that exists, but I wish it was for your case! (I just tried it in case...but nope)

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