Efficiency of Queries

[Anonymous]

Dear all,

I am wondering?

If I have Table 1, Table 2 and Table 3, Query A, Query B and Query C.

Query A produces a scalar date value which is the Max of dates in Table 1.

Query B runs a Select Rows operation using the result of Query A to filter the range of dates returned from Table 2.

Query C runs a Select Rows operation using the result of Query A to filter the range of dates returned from Table 3.

Is Query A only calculated once and the value used in Query B and Query C, or is Query A calculated separately for both Query B and Query C.

If this is true what is the best way to do things so that I only need to calculated Query A once to be used by both Query B and Query C rather than having to calculate it multiple times.   

[Eric_Zhang]

[removed]

[hohlick]

Hi @Eric_Zhang

Can you please explain this: 

---

If you'd like the Query1 run only once, then you can create it as a function.

Is turnung a query into an invoked function result prevents it from recalculating when other queries linked to it? Or it depends from data source?

How it could be referenced to this thread? 

[Eric_Zhang]

@hohlick @Anonymous

My bad, as the function in M is called manually in my case so I thought it persists as a constant and won't be re-evulated. I'm deleting that part in my reply to avoid missleading.

Thanks for that link, it is really really helpful.

[Anonymous]

Thank you very much. I will try that out as I update some of my data models. 

[Anonymous]

Dear all,

I am wondering?

If I have Table 1, Table 2 and Table 3, Query A, Query B and Query C.

Query A produces a scalar date value which is the Max of dates in Table 1.

Query B runs a Select Rows operation using the result of Query A to filter the range of dates returned from Table 2.

Query C runs a Select Rows operation using the result of Query A to filter the range of dates returned from Table 3.

Is Query A only calculated once and the value used in Query B and Query C, or is Query A calculated separately for both Query B and Query C.

If this is true what is the best way to do things so that I only need to calculated Query A once to be used by both Query B and Query C rather than having to calculate it multiple times.